Q&A - PSLE Math
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Hope this help, please correct me if I was wrong.
a) 11:30am to 3:30pm = 4 hours
Van was 80 km/hour
4 x 80 = 320 km
Van was 320 km from t=Town X
b) truck started 2 hours later which was 1:30pm
1:30pm to 3:30pm = 2 hours
Truck was 54 km/hour
2 x 54 = 108 km
At 3:30 pm:
Van was (350-320)km = 30km away to Town Y
Truck was 108 km away from Town Y
108 ā 30 = 78 km
So the distance between the van and the truck at 3:30 pm was 108 km -
small:
(a) 320 kmHope this help, please correct me if I was wrong.
a) 11:30am to 3:30pm = 4 hours
Van was 80 km/hour
4 x 80 = 320 km
Van was 320 km from t=Town X
b) truck started 2 hours later which was 1:30pm
1:30pm to 3:30pm = 2 hours
Truck was 54 km/hour
2 x 54 = 108 km
At 3:30 pm:
Van was (350-320)km = 30km away to Town Y
Truck was 108 km away from Town Y
108 ā 30 = 78 km
So the distance between the van and the truck at 3:30 pm was 108 km
(b)Distance that the truck had travelled-> 54 X 2 = 108 km
Distance between the truck and van-> (108+320)-350
= 428-350
= 78 km -
Thanks vanilla cake and small for your help. Realise i typed the wrong answer. For (a) it should be 320km and (b) 78km.
Thanks. I've one more question. Ans is 360.![](\"http://farm4.static.flickr.com/3654/3525605596_a43c5698aa_o.png\")
http://farm4.static.flickr.com/3654/3525605596_a43c5698aa_o.png\">
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mathsparks:
Hi Mathsparks,Thanks vanilla cake and small for your help. Realise i typed the wrong answer. For (a) it should be 320km and (b) 78km.
Thanks. I've one more question. Ans is 360.
Yr qn and solution can be found in this http://prischoolmaths.blogspot.com/search/label/Maths-Percentage
Reference : Maths - Percentage dated 8 Feb 2009.
Hope this helps.
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Thanks so much vanilla cake for your help. I often wonder where you find so much time to help us ksps when you're busy with school work yourself. All these should contribute to CIP for you. :lol:
Maybe you should ask chief to write you a glowing testimony on behalf of us. -
Maths Questions from CNA forum.
http://www.channelnewsasia.com/discussion/forum.htm
1. Courier A takes 10 hours to deliver a parcel from Town X to Town Y. Courier B takes 12 hours to deliver the parcel along the same route. If the speed of Courier A is 9km/h faster than that of Courier B, find the speed of Courier A.
2. There were some apples at a fruit stall. In the morning, the number of apples sold was 2/5 of the apples left. In the afternoon, another 44 apples were sold. The total number of apples sold was 6 less than 9/14 of the number apples the fruit stall had at first. How many apples were there at first?
3. In a grooming workshop organised by the school, 75% of the pupils participated were girls. 49 girls and 3 boys quitted halfway and went home. The remaining pupils were organised into groups of 10 for group discussion. There were 3 boys in each group. How many pupils participated in the grooming workshop at first?
4. There were some apples and oranges in a box. 80% of the fruits in the box were apples. Ali sold 63 apples and 9 oranges. He packed the remaining fruits into packets of 12 apples and oranges. Each packet of fruits has 3 oranges. Find the total number of oranges Ali had at first.
5. When Mrs Lee was 40 years old, her son was twice her daughter's age. Mrs Lee will be twice her son's age when her daughter is 28 years old. How old will Mrs Lee be when her daughter is 20 years old?
6. In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?
7. Tom wants to complete a jigsaw puzzle. On the first day, he fitted 20% of the puzzle. On the second day he fitted another 60 pieces. The ratio of fitted to non-fitted pieces is now 2:5. How many pieces are there in the jigsaw puzzle?
8. Shop X sells a watch for $2400 which is 25% less than what Shop Y sells. During a sale, both shops offer an equal percentage discount. Mr Lee bought the watch in Shop Y and paid $520 more than the discounted price in Shop X. What is the percentage discount given by both shops?
9. The ratio of Ryan's pocket money to John's pocket money was 3 : 2. After Ryan saved $15 and John spent $8, the ratio of Ryan's pocket money to John's pocket money was 3 : 1. How much money did Ryan have at first?
10. John had $228 and Kevin had $204. Kevin spent thrice as much as John. If John had thrice as much money as Kevin after spending, how much did Kevin spend? -
Vanilla Cake:
Hi Vanilla Cake,
Hi Mathsparks,mathsparks:
Thanks vanilla cake and small for your help. Realise i typed the wrong answer. For (a) it should be 320km and (b) 78km.
Thanks. I've one more question. Ans is 360.
Yr qn and solution can be found in this http://prischoolmaths.blogspot.com/search/label/Maths-Percentage
Reference : Maths - Percentage dated 8 Feb 2009.
Hope this helps.
Just want to thank you for send this link; all the Math questions are good. I have printed out all the questions/answers and compiled into a booklet for my girl as reference.
You rock! -
Hi mathsparks/mummyjoyce,
Thks. I have a younger sister who will be taking PSLE in 2011, that's why I still have to keep in touch with PSLE matters.
Let me try those qns posted by tianzhu from CNA forum. Pls correct me if I am wrong. TIA.
Q1
Courier A takes 10 hours to deliver a parcel from Town X to Town Y. Courier B takes 12 hours to deliver the parcel along the same route. If the speed of Courier A is 9km/h faster than that of Courier B, find the speed of Courier A.
Time
A : B
10 : 12
5 : 6
Speed
A : B
6 : 5
1 unit-> 9 km/h (difference)
6 units-> 9 x 6 = 54 km/h
Speed of Courier A is 54 km/h
Q2
There were some apples at a fruit stall. In the morning, the number of apples sold was 2/5 of the apples left. In the afternoon, another 44 apples were sold. The total number of apples sold was 6 less than 9/14 of the number apples the fruit stall had at first. How many apples were there at first?
Need to draw a model to solve this qn. From the model, you will be able to see that 44 apples sold in the afternoon + 6 -> 5 units
5 units -> 50
1 unit -> 10
14 units -> 140
Number of apples at first were 140.
Q3
In a grooming workshop organised by the school, 75% of the pupils participated were girls. 49 girls and 3 boys quitted halfway and went home. The remaining pupils were organised into groups of 10 for group discussion. There were 3 boys in each group. How many pupils participated in the grooming workshop at first?
Before
Girls -> 75%
Boys -> 25%
G : B
3: 1
After
G : B
7 : 3
Since the number of girls was thrice as many as the boys,
(7 units + 49) = 3(3 units + 3 )
7 units + 49 = 9 units + 9
2 units = 40
1 unit = 20
Number of pupils at first-> (20x7) + (20x3) + 49 + 3 = 252
Q4
There were some apples and oranges in a box. 80% of the fruits in the box were apples. Ali sold 63 apples and 9 oranges. He packed the remaining fruits into packets of 12 apples and oranges. Each packet of fruits has 3 oranges. Find the total number of oranges Ali had at first.
Before
A : O
4 : 1 (Apples were 4 times as many as oranges)
After
A : O
9 : 3
3 : 1
Sold 63 apples and 9 oranges,
4(unit+9) = 3 units + 63
4 units + 36 = 3 units + 63
1 unit = 27
Total number of oranges at first-> 27+9 = 36
Q5
When Mrs Lee was 40 years old, her son was twice her daughter's age. Mrs Lee will be twice her son's age when her daughter is 28 years old. How old will Mrs Lee be when her daughter is 20 years old?
This was qn 45 from SCGS (Pri) 2007 P6 Prelim.
Let the age of the daughter be n
When Mrs Lee was 40 yrs old,
Son-> 2n
Daughter-> n
When daughter was 28 yrs old,
Mrs Lee -> 2(28+n) = 56 + 2n
Son-> 28+n
40-2n=28+n
3n=12
n=4
When daughter was 4 yrs old, Mrs Lee would be 40 yrs old.
When daughter is 20 yrs old, Mrs Lee will be 40+16 = 56 yrs old
Pls see the http://road-to-psle.blogspot.com/2007_11_01_archive.html that was posted on 07 Nov 07.
Q6
In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?
Before
F : M
3 : 1
75 Females and 5 males left
After
F : M
7 : 3
7 units + 75 = 3(3 units+5)
7 units + 75 = 9 units + 15
2 units = 60
1 unit = 30
Number of people at first-> (30x3)+ 5 + (30x7) + 75
= 90+5+210+75 = 380
Q7
Tom wants to complete a jigsaw puzzle. On the first day, he fitted 20% of the puzzle. On the second day he fitted another 60 pieces. The ratio of fitted to non-fitted pieces is now 2:5. How many pieces are there in the jigsaw puzzle?
Before
F : NF
1 : 4
7 : 28
After
F : NF
2 : 5
10: 25
3 units-> 60
1 unit -> 20
35 units-> 700
Number of pieces in the jigsaw puzzle is 700
Q8
Shop X sells a watch for $2400 which is 25% less than what Shop Y sells. During a sale, both shops offer an equal percentage discount. Mr Lee bought the watch in Shop Y and paid $520 more than the discounted price in Shop X. What is the percentage discount given by both shops?
Shop X -> 2400
Shop Y -> 2400/75 x 100 = 3200
Difference -> 3200-2400 = 800
Difference between the 2 shops-> 520
Percentage discount given by both shops-> (800-520)/800 x 100 = 35%
Q9
The ratio of Ryan's pocket money to John's pocket money was 3 : 2. After Ryan saved $15 and John spent $8, the ratio of Ryan's pocket money to John's pocket money was 3 : 1. How much money did Ryan have at first?
Before
R : J
3 : 2
Ryan saved $15 and John spent $8
After
R : J
3 : 1
2(3 units - 15) = 3(1 unit + 8 )
6 units - 30 = 3 units + 18
3 units = 54
1 unit = 18
Amount of money that Ryan had at first-> (18x3)-15 = $ 39
Q10
John had $228 and Kevin had $204. Kevin spent thrice as much as John. If John had thrice as much money as Kevin after spending, how much did Kevin spend?
Draw a model and you will see that :
8 units = 3(228)-204 = 480
1 unit = 60
Amount of money that Kevin spent-> 204-60 = $ 144 -
Vanilla Cake:
Hi Vanilla Cake,Hi mathsparks/mummyjoyce,
Thks. I have a younger sister who will be taking PSLE in 2011, that's why I still have to keep in touch with PSLE matters.
Let me try those qns posted by tianzhu from CNA forum. Pls correct me if I am wrong. TIA.
Q1
Courier A takes 10 hours to deliver a parcel from Town X to Town Y. Courier B takes 12 hours to deliver the parcel along the same route. If the speed of Courier A is 9km/h faster than that of Courier B, find the speed of Courier A.
Time
A : B
10 : 12
5 : 6
Speed
A : B
6 : 5
1 unit-> 9 km/h (difference)
6 units-> 9 x 6 = 54 km/h
Speed of Courier A is 54 km/h
Q2
There were some apples at a fruit stall. In the morning, the number of apples sold was 2/5 of the apples left. In the afternoon, another 44 apples were sold. The total number of apples sold was 6 less than 9/14 of the number apples the fruit stall had at first. How many apples were there at first?
Need to draw a model to solve this qn. From the model, you will be able to see that 44 apples sold in the afternoon + 6 -> 5 units
5 units -> 50
1 unit -> 10
14 units -> 140
Number of apples at first were 140.
Q3
In a grooming workshop organised by the school, 75% of the pupils participated were girls. 49 girls and 3 boys quitted halfway and went home. The remaining pupils were organised into groups of 10 for group discussion. There were 3 boys in each group. How many pupils participated in the grooming workshop at first?
Before
Girls -> 75%
Boys -> 25%
G : B
3: 1
After
G : B
7 : 3
Since the number of girls was thrice as many as the boys,
(7 units + 49) = 3(3 units + 3 )
7 units + 49 = 9 units + 9
2 units = 40
1 unit = 20
Number of pupils at first-> (20x7) + (20x3) + 49 + 3 = 252
Q4
There were some apples and oranges in a box. 80% of the fruits in the box were apples. Ali sold 63 apples and 9 oranges. He packed the remaining fruits into packets of 12 apples and oranges. Each packet of fruits has 3 oranges. Find the total number of oranges Ali had at first.
Before
A : O
4 : 1 (Apples were 4 times as many as oranges)
After
A : O
9 : 3
3 : 1
Sold 63 apples and 9 oranges,
4(unit+9) = 3 units + 63
4 units + 36 = 3 units + 63
1 unit = 27
Total number of oranges at first-> 27+9 = 36
Q5
When Mrs Lee was 40 years old, her son was twice her daughter's age. Mrs Lee will be twice her son's age when her daughter is 28 years old. How old will Mrs Lee be when her daughter is 20 years old?
This was qn 45 from SCGS (Pri) 2007 P6 Prelim.
Let the age of the daughter be n
When Mrs Lee was 40 yrs old,
Son-> 2n
Daughter-> n
When daughter was 28 yrs old,
Mrs Lee -> 2(28+n) = 56 + 2n
Son-> 28+n
40-2n=28+n
3n=12
n=4
When daughter was 4 yrs old, Mrs Lee would be 40 yrs old.
When daughter is 20 yrs old, Mrs Lee will be 40+16 = 56 yrs old
Pls see the http://road-to-psle.blogspot.com/2007_11_01_archive.html that was posted on 07 Nov 07.
Q6
In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?
Before
F : M
3 : 1
75 Females and 5 males left
After
F : M
7 : 3
7 units + 75 = 3(3 units+5)
7 units + 75 = 9 units + 15
2 units = 60
1 unit = 30
Number of people at first-> (30x3)+ 5 + (30x7) + 75
= 90+5+210+75 = 380
Q7
Tom wants to complete a jigsaw puzzle. On the first day, he fitted 20% of the puzzle. On the second day he fitted another 60 pieces. The ratio of fitted to non-fitted pieces is now 2:5. How many pieces are there in the jigsaw puzzle?
Before
F : NF
1 : 4
7 : 28
After
F : NF
2 : 5
10: 25
3 units-> 60
1 unit -> 20
35 units-> 700
Number of pieces in the jigsaw puzzle is 700
Q8
Shop X sells a watch for $2400 which is 25% less than what Shop Y sells. During a sale, both shops offer an equal percentage discount. Mr Lee bought the watch in Shop Y and paid $520 more than the discounted price in Shop X. What is the percentage discount given by both shops?
Shop X -> 2400
Shop Y -> 2400/75 x 100 = 3200
Difference -> 3200-2400 = 800
Difference between the 2 shops-> 520
Percentage discount given by both shops-> (800-520)/800 x 100 = 35%
Q9
The ratio of Ryan's pocket money to John's pocket money was 3 : 2. After Ryan saved $15 and John spent $8, the ratio of Ryan's pocket money to John's pocket money was 3 : 1. How much money did Ryan have at first?
Before
R : J
3 : 2
Ryan saved $15 and John spent $8
After
R : J
3 : 1
2(3 units - 15) = 3(1 unit + 8 )
6 units - 30 = 3 units + 18
3 units = 54
1 unit = 18
Amount of money that Ryan had at first-> (18x3)-15 = $ 39
Q10
John had $228 and Kevin had $204. Kevin spent thrice as much as John. If John had thrice as much money as Kevin after spending, how much did Kevin spend?
Draw a model and you will see that :
8 units = 3(228)-204 = 480
1 unit = 60
Amount of money that Kevin spent-> 204-60 = $ 144
You've got them all correct. Thanks -
Among the 10 questions posted by tianzhu, Q5 is the hardest. Students who can do that question (without using guess and check) are considered very strong and will most likely score A* for PSLE maths.
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