Q&A - PSLE Math

[tianzhu]

jarenchuatw:

Another question in need help to solve:


2/3 of the fruits at a stall were oranges. 3/4 of the remaining fruits were appleas and the rest were banaanas. There were 150 more oranges than apples. After selling some apples, 10% of the remaining fruits were apples. How many apples were sold?

Thanks

Hi

A neat way is to use MD or you may also work with units and parts.

Draw a long bar and divide into 3 equal parts.

Further divide each part into 4 smaller units.

8 units ------- oranges
3 units ------ apples
1 unit ------- banana

8 - 3 ------ 5

5 units ------ 150

1 unit ------ 30

Oranges ------- 240

Apples ------- 90

Banana -------- 30

Let’s represent the remaining number of apple sold as A

A -------- 1p

270 +A -------- 10p

Equalize the parts

10A -------- 10p

270 + A -------- 10A

9A ------- 270

A -------- 30

Number of apples sold -------- 90 – 30 -------60

Best wishes

[Shimmer]

Need help on this question.


Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil, find the cost of a pencil.

[pixiedust]

Shimmer:

Need help on this question.


Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil, find the cost of a pencil.

Total spent $21.60
Spent on notebooks -> $9.60+$2.40= $12
Spent on pencils -> $9.60

#pencils -> 4u
#notebooks -> 1u

1u notebook -> $12
1u pencils -> $9.60/4= $2.40

($12-$2.40) / 3.20 = 3 -> Hence, he bought 3 notebooks.
Therefore, he bought 12 pencils.
12 pencils -> $9.60
1 pencil -> $0.80

[2632parent]

Councillor Thanks for the solution but I have problem understanding how you get

2u + 2(676) ----- 1504

[tianzhu]

2632parent:

Councillor Thanks for the solution but I have problem understanding how you get

2u + 2(676) ----- 1504

Hi

14 units + 2 parts ------- 1504

2 units + (12 units + 2 parts) ------- 1504

2 units + (6 units + 1 part) + (6 units + 1 part) ------- 1504

6 units + 1 part ----- 676

Hence, 2 units + 2(676) ------- 1504

Best wishes

[2632parent]

A very big thank you to both tianzhu and councillor , now I really … Understanding. Thank you for your explaination and patience. Luv you both…

[jonaandr]

Help needed for these 2 questions - many thanks in advance!


1) 2 , 5 , 17 , 71 , X , 2159
Study the above number pattern. Find the value of X.

Ans: 359, pls tell me why.

2) When Karen left her house and drove at an average speed of 56km/h, she would reach Town X at 1900. If she decided to drive at an average speed of 72km/h, she would reach Town X at 1700. At what time did she leave her house?

[2632parent]

Any one more question


1) Mr lim had some red and green beads. 60% of his beads were red and the rest were green. He lost some of his red beads and the percentage of the beads which were red decreased by 40%. He then had 760 red and green beads left. How meant red beads did he lose?

Many thanks in advance.

[shawnlim88]

jonaandr:

Help needed for these 2 questions - many thanks in advance!


1) 2 , 5 , 17 , 71 , X , 2159
Study the above number pattern. Find the value of X.

Ans: 359, pls tell me why.

2) When Karen left her house and drove at an average speed of 56km/h, she would reach Town X at 1900. If she decided to drive at an average speed of 72km/h, she would reach Town X at 1700. At what time did she leave her house?

hi
Qn1: No idea.
Qn2:
S = Dist/TIme
Let Starting TIme Be S. Distance be D

56 = (D) / (19-S)
72 = (D) / (17-S)

cross multiply
72(17-S) = 56(19-S)
1224 -72S = 1064 - 56S
16S = 160
S = 10

starting Time at 10:00 hrs

not sure if this is correct

[MathIzzzFun]

jonaandr:

Help needed for these 2 questions - many thanks in advance!


1) 2 , 5 , 17 , 71 , X , 2159
Study the above number pattern. Find the value of X.

Ans: 359, pls tell me why.

Hi

where is this question from?

2nd number = 1st number x 2 + 1
3rd number = 2nd number x 3 + 2
4th number = 3rd number x 4 + 3
5th number = 4th number x 5 + 4 = 71 x 5 + 4 = 359

cheers.