Q&A - PSLE Math

[ruohoo97]

Mrs Yeo bought some cakes for her class pupils. the girls received twice as many as the boys. There were an equal number of girsl and boys in her class. Each boy ate 4/7 of a cake and they finished all the cakes that were given to them. Each girl ate 1/3 of a cake and they had 8 and 1/2 cakes left. How many cakes did Mrs Yeo buy?


Thanks in advance!

[tianzhu]

ruohoo97:

Mrs Yeo bought some cakes for her class pupils. the girls received twice as many as the boys. There were an equal number of girsl and boys in her class. Each boy ate 4/7 of a cake and they finished all the cakes that were given to them. Each girl ate 1/3 of a cake and they had 8 and 1/2 cakes left. How many cakes did Mrs Yeo buy?


Thanks in advance!

Hi

Would you like to share where is this question from?

I have an answer of 18 cakes.

However, I find it a bit strange, if you try to find the number of boys, you’ll end up with not a whole number.

Do you have the answer from the WS?

Best wishes

[ruohoo97]

Yes, I find it strange too. It’s from ACSJ P6 2

SA1, 2011. I don’t have standard answer as it was given by my DD’s teacher for this June holiday homework.

[Michaelia0816]

Need help with those following hard question, from practice paper!


1) 10 cooks working for 8 hours each, can prepare a meal for 160 people. How many cooks will be needed to prepare a meal for 220 people if they are required to prepare in 5 hours?

[Michaelia0816]

2) In an army camp of 1200 men have sufficient rations for 25 days at the rate of 2400g per man per day. If 300 men join, and the rations are reduced to 2000g per man per day. How long will the food last all of them?

[Michaelia0816]

3) A contractor agrees to lay a road 3000m long in 30 days. He employs 50 men who work for 8 hours a day. After 20 working days, he finds that only 1200m of the road is completed. How many more men should be employ to finish the work on time if each man now works 10 hours a day?

[Michaelia0816]

4) Mrs Wong gave birth to 4 children in 4 consecutive years. Today, she discovered that the product of the ages, in years, of the 4 children is 3024. How old are her 4 children now?


I know the answer, it should be 6,7,8,9 but am I suppose to add the ages together to get the final answer?

[sleepyqueen]

Michaelia0816:

4) Mrs Wong gave birth to 4 children in 4 consecutive years. Today, she discovered that the product of the ages, in years, of the 4 children is 3024. How old are her 4 children now?


I know the answer, it should be 6,7,8,9 but am I suppose to add the ages together to get the final answer?

3024 = 2 x 2 x 2 x 2 x 3 x 7 x 9

from here we can see 2x2x2 = 8, 2x3 = 6, 7, 9
hence ages of the kids are 6,7,8,9

[Michaelia0816]

Thank you, can you also help with another challenging questions?

[sleepyqueen]

Michaelia0816:

2) In an army camp of 1200 men have sufficient rations for 25 days at the rate of 2400g per man per day. If 300 men join, and the rations are reduced to 2000g per man per day. How long will the food last all of them?

total rations available = 1200 X 25 X 2400 = 72000000

After 300 join = 1500 men
per man rations = 2000g

No of days to last = 72000000/(1500 x 2000) = 72000000/3000000 = 24 days