Q&A - PSLE Math

[jarenchuatw]

Got 2 questions here needing help to solve:


Q1 A shopkeeper had some track shoes. 3/7 of them were brand X, 1/4 of the remainder were Brand Y and the rest were Brand Z. The ratio of the number of pairs of Brand X sold to the number of Brand Y to the number of Brand Z sold was 1:2:4. He sold 1/5 of all the shoes and was paid &840. How many pairs of Brand Z had he at
first?

Q2 see image attached

[zombie]

Hello, can someone please help me to solve these percentage questions? :oops:


1)John had 55% as many stickers as marbles. After he gave an equal number of stickers and marbles to Rick, he had 5/8 as many stickers as marbles. How many stickers and marbles did he give away if he had 168 marbles in the end?

2)Anne, Ben and Chris shared the cost of their seafood dinner. Anne paid 40% the total amount and Ben paid 30% of what Anne and Chris paid. If Ben paid $36 less than Chris, how much did Anne pay?

3)Mr Low had 40% more cows than sheep. After he sold 375 cows and bought 375 sheep, he had 80% lesser cows than sheep. How many sheep did he have in the end?

4)Adam has 30% as many stickers than Ben and 25% more cards than Chris. If they have a total of 462 stickers, how many stickers does Chris have?

5)Kelly had 40% as much money as Mandy. After Mandy spent $66 on a dress, the percentage of Kelly’s money increased to 60%. How much money did Kelly have?

6)There were 40% of girls in the Science Club. After another 30 girls joined the Science Club, the percentage of girls increased by 15%. How many pupilswere there in the club at the end ?

7)There were 165 more chickens than ducks on a farm. If 60% of the chickens and 20% of the ducks were sold, the number of chickens left will be twice the number of ducks left. How many chickens were sold?

8)John had 55% as many stickers as marbles. After he gave an equal number of stickers and marbles to Rick, he had 5/8 as many stickers as marbles. How many stickers and marbles did he give away if he had 168 marbles in the end?

Thank you !

[2632parent]

Hi tianzhu how do you get 16u for the apples and 20u for the orange. Thank you.

[tianzhu]

2632parent:

Hi tianzhu how do you get 16u for the apples and 20u for the orange. Thank you.

Hi

Apples:Oranges ------- 4:5 ------ 16:20

25% ------ 1/4

A common multiple for 4 and 5 is 20.

Best wishes

[tianzhu]

jarenchuatw:

Got 2 questions here needing help to solve:


Q1 A shopkeeper had some track shoes. 3/7 of them were brand X, 1/4 of the remainder were Brand Y and the rest were Brand Z. The ratio of the number of pairs of Brand X sold to the number of Brand Y to the number of Brand Z sold was 1:2:4. He sold 1/5 of all the shoes and was paid &840. How many pairs of Brand Z had he at
first?

Q2 see image attached

Hi

For Q1, I think some information might be missing.The amount of money earned for each pair of shoes for different brands is required.

For Q2, please attach the image.

Best wishes

[2632parent]

Oh my goodness how silly of me, thank you I understand now. Well have another question on speed , please help.


1) Abdul, Bernard and Chi Hao were all standing in a straight line waiting for the race to start. Chi Hao was 300m ahead of Bernard and Bernard was 100m ahead of Abdul. At 9a.m, they started the race. Abdul overtook Bernard in 5mins.
In another 5 mins, Abdul overtook Chi Hao. If Bernard’s speed is 150m/mins, at what time did Bernard overtake Chi Hao?

Thank you very much

[jarenchuatw]

You right, Tianzhu. I forgot to put in the following info:


X:$8 per pair
Y: $6 perbpair
Z: $10 per pair

[jarenchuatw]

http://i50.tinypic.com/2ugyn3q.jpg\"> And for Q2, attaching the image here.

[tianzhu]

2632parent:

1) Abdul, Bernard and Chi Hao were all standing in a straight line waiting for the race to start. Chi Hao was 300m ahead of Bernard and Bernard was 100m ahead of Abdul. At 9a.m, they started the race. Abdul overtook Bernard in 5mins.
In another 5 mins, Abdul overtook Chi Hao. If Bernard's speed is 150m/mins, at what time did Bernard overtake Chi Hao?

Thank you very much

Hi

Good Morning.

For Speed questions, it helps to start with a simple diagram.

This question touches on motion in the same direction where the faster runner overtakes the slower one. An important point to note is at the point of overtaking, the distance covered by both runners will be the same.

Bernard was 100m ahead of Abdul with a speed of 150m/min
Abdul overtook Bernard in 5min.

In 5 min, Bernard covered 150*5 or 750m/min

Abdul ------- 100 + 750 ------ 850 m/min

Hence, Abdul’s speed ------- 850/5 ------ 170m/min

Chi Hao was 300m ahead of Bernard.This means Chi hao was 400 m ahead of Abdul.

In 10 min, Abdul covered 1700 m

In 10 min ,Chi Hao ran 1300 m

Chi Hao’s speed ------ 1300/10 ------- 130 m/min.

In 1 min, Bernard is 20 m faster than Chi Hao

In 15 min, Bernard is 300 m faster than Chi Hao.

Bernard overtook Chi Hao at 9.15 am

Best wishes

[2632parent]

Good morning tianzhu, thank you for the solution.