Q&A - PSLE Math
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if it’s for p6 and they are taught algebra and simple simultaneous equations, they are allowed to solve it as merlion has shown.
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faith2u:
Solution for this question:[Moderator's note: Topics merged.]
1). Father gave Gary $570 and his sister $250. After their mother has
given them an equal amount, Gary’s amount was twice as much as his
sister’s. How much money did their mother give to each of them?
(Ans : $70)
http://www.postimage.org/image.php?v=Pq10zO2i -
It can be solved by model too. But I do not know how to post a diagram here. Anyway, you can draw 4 boxes represent Fish balls and 2 boxes (different box size as Fish ball) represent Sotong balls. the total of these 6 boxes is 520. Now you draw 1 box (because of 0.25)of Fish balls and 1 box (because of 0.5) of Sotong balls, the new total is 180. So 2 boxes of Fish balls and 2 boxes of Sotong balls is 360. Therefore 2 boxes of Fishball are 160. If 2 boxes of Fish balls are 160, then 4 boxes must be 320. I hope this helps.
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faith2u:
[Moderator's note: Topics merged.]
1). Father gave Gary $570 and his sister $250. After their mother has
given them an equal amount, Gary’s amount was twice as much as his
sister’s. How much money did their mother give to each of them?
(Ans : $70)
2). 20 more men than women were invited to a concert. ¾ of the men
and 2/3 of the women attended the concert, while 26 people did not
show up.
How many people were invited to the concert? (Ans : 92)
3). An ant is climbing up a slippery wall. After every 3cm it climbs up, it
slides 1cm. It takes 3 seconds for it to climb up 1cm and 1 second for
it to slide 1cm.
(a). How long does it take to climb 12 cm? (Ans : 1min)
(b). How long does it take to climb 60cm? (Ans : 4min 56sec)
Q1 (Draw model)
G -- $570 + M -- 2 units
S -- $250 + M -- 1 unit
1 unit -- 570 - 250 = $320
M -- 320 - 250 = $70
Q2 (Draw model)
M -- 12 u + 20
W -- 12 u
Did not attend
M -- 3 u + 5
W -- 4 u
7 u --> 26 - 5 = 21
1 u --> 21 / 7 = 3
24 u + 20 = 24 x 3 + 20 = 92 invited.
Q3
1 cycle --> + 3 cm - 1 cm = 2 cm
1 cycle --> 3 x 3 + 1 = 10 s
12 cm --> 5 cycles + 2 cm = 5 x 10 + 2 x 3 = 56 s
[Not 6 cycles as the ant will not slip in the last 2 cm.
Answer of 1 min is not correct - it has used 6 cycles]
60 cm --> 29 cycles + 2 cm = 29 x 10 + 2 x 3 = 296 s = 4 min 56 s. -
AnnT2009:
Q1Please help,
Q1 Mary and Jason each have some money. If Mary spent$80 per day and Jason spent $40 per day. Mary will have $500 left when Jason has spent all his money. If Mary spent $40 per day and Jason spent $80 per day. Mary will have $1100 left when Jason spent all his money. What is the amount of money Jason has?
Ans:$400
Q2 Mr Tan bought three times as many badges as toy cars and spent $144 in total. He spent $84 more on toy cars than on badges. Given that a toy car cost $10.40 more than a badge. What is the cost of a badge?
Ans:$1
TIA.
Case 1 : Spend in N days
Mary: 1 unit - $80N = $500
Jason : 1 part - $40N = $0
Case 2 : Spend in M days
Mary : 1 unit - $40M = $1100
Jason : 1 part - $80M = $0
1 part = $40N = $80M
N = 2M
1 unit = $80N +$500 = $40M +$1100
$160M-$40M = $600
$120M = $600
M=5 days
Amt of money Jason has, i.e 1 part = $80 x 5 = $400 -
AnnT2009:
QtyPlease help,
Q2 Mr Tan bought three times as many badges as toy cars and spent $144 in total. He spent $84 more on toy cars than on badges. Given that a toy car cost $10.40 more than a badge. What is the cost of a badge?
Ans:$1
TIA.
Badges : 3 units
Toy Cars : 1 unit
Unit Price
Badges : 1 part
Toy car : 1 part + $10.40
Total Value
Badges : (3 units x 1 part)
Toy car : 1 unit x (1 part +$10.40)
(4 units x 1 part) + (1 unit x $10.40) = $144 ------- Eqn 1
(1 unit x $10.40) - (2 units x 1 part) = $84
(2 units x $10.40) - (4 units x 1 part) = $ 168 -------- Eqn 2
Eqn 1 + Eqn 2
(3 units x $10.40) = $ 312
1 unit = 10
40 x 1 part = $144 - $104
1 part = 1
1 part - unit price of badge = $1 -
Dear all,
Please assist me with these questions
1. See diagram attached
2. Adrian and Bob started driving at the same time. Adrian takes 6 hours to complete his journey, Bob takes 9 hours to complete his journey.
After 3 hours, both men are left with the same distance to travel.
What is the ratio of Bob's to Adrian's distance ?
3. A, B, C, D share in a gift equally. D forgot to bring his share, so the rest paid for him first. Cindy paid 3/5 of (A+B)'s share. B paid $10 more than A. The next day, Danny returned $24 to C. How much did D return to A and B?
Many, many thanks in advanceDharma:
http://www.postimage.org/
QtyAnnT2009:
Please help,
Q2 Mr Tan bought three times as many badges as toy cars and spent $144 in total. He spent $84 more on toy cars than on badges. Given that a toy car cost $10.40 more than a badge. What is the cost of a badge?
Ans:$1
TIA.
Badges : 3 units
Toy Cars : 1 unit
Unit Price
Badges : 1 part
Toy car : 1 part + $10.40
Total Value
Badges : (3 units x 1 part)
Toy car : 1 unit x (1 part +$10.40)
(4 units x 1 part) + (1 unit x $10.40) = $144 ------- Eqn 1
(1 unit x $10.40) - (2 units x 1 part) = $84
(2 units x $10.40) - (4 units x 1 part) = $ 168 -------- Eqn 2
Eqn 1 + Eqn 2
(3 units x $10.40) = $ 312
1 unit = 10
40 x 1 part = $144 - $104
1 part = 1
1 part - unit price of badge = $1 -
Hi Drdj
Q1. Missing info in qn …is it triangle CEA or CED?
Q2
Total dist travelled :
Adr - 6 x Speed of A
Bob - 9 x Speed of B
After 3 hrs
Adr travelled - 3x Speed of A
Bob travelled - 3 x Speed of B
Both left w/ same dist to travel after 3 hrs
3 x Speed of A = 6 X Speed of B
Speed of A = 2 X Speed of B
Total distance travelled
Adr - 6 x 2 x Speed of B
Bob - 9 x Speed of B
Ratio of distance travelled - A:B = 12 : 9 = 4:3 -
Drdj:
I take your missing info on the area of triangle as CED.
http://www.postimage.org/
Draw a dotted line to cut through E and label X on the left side and Y on the right side.
Area of rectangle ABXY-> 80 x 2 = 160 cm2
Area of rectangle XYDC-> 60 % of the rectangle ABCD
40%-> 160 cm2
100%->400 cm2
Area of rectangle ABCD is 400 cm2
[quote]Adrian and Bob started driving at the same time. Adrian takes 6 hours to complete his journey, Bob takes 9 hours to complete his journey.After 3 hours, both men are left with the same distance to travel.
What is the ratio of Bob's to Adrian's distance ?[/quote]Adrian
6 h-> 1 whole journey
3 h-> 1/2 journey
Remaining distance -> 1/2 journey = 2/4 journey
Bob
9 h -> 1 whole journey
3 h-> 1/3 journey
Remaining distance -> 2/3 journey
Ratio of Bob's to Adrian's distance -> 3 : 4 -
A, B, C, D share in a gift equally. D forgot to bring his share, so the rest paid for him first. Cindy paid 3/5 of (A+B)'s share. B paid $10 more than A. The next day, Danny returned $24 to C. How much did D return to A and B?
Draw a model:
4 equal blocks and divide into 5 parts for A, B, C and D.
Amount of money paid in units for C-> 3/5x(5+5)= 6 units
Amount of money C paid in units for D-> 6-5 = 1 unit
So, 1 unit-> $24
4 units-> $ 96
Amount of money that D returned to A and B was $ 96
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