Q&A - PSLE Math

[tianzhu]

small:

Please help on the following question (from my DS's Maths homework book) and many thnaks in advance.


Question
In a pastry shop, the number of cakes was twice the number of cream puffs. After 90 cakes and 42 cream puffs were sold, the ratio of the number of cakes left to the number of cream puffs left was 2 : 5. How many cakes and cream puffs were in the shop at first?

Hi small

Please check your question with your source.

Best wishes

[small]

Another solution which using algebra method.


Let:
D – Ducks (2legs)
C – Cows (4legs)

Total number of these animals -> D+C
Total number of their legs -> 2D+4C

(D+C)/(2D+4C)= 8/23
23D+23C=16D+32C
7D=9C
D/C = 9/7

Fraction of ducks / cows = 9/7.

[small]

tianzhu:

small:

Please help on the following question (from my DS's Maths homework book) and many thnaks in advance.


Question
In a pastry shop, the number of cakes was twice the number of cream puffs. After 90 cakes and 42 cream puffs were sold, the ratio of the number of cakes left to the number of cream puffs left was 2 : 5. How many cakes and cream puffs were in the shop at first?

Hi small

Please check your question with your source.

Best wishes

Thanks tianzhu, will ask my DS check with his form teacher.

This question is Q7 page 70 of 'My PALS Are Here Maths Homework (2nd Editon) 6A'

[tianzhu]

Hi small


Good Morning.

You’ll get an answer in decimals.

Cake: cream puffs ------ 2 units: 1 unit
Cake: cream puffs ----- -90: -42
Cake: cream puffs ------ 2 parts: 5 parts

Cross multiply or equalising the parts

10 units – 450 ------ 2 units – 84
8 units ------- 366
1 unit ------- 45.75

Hence, you’ll end up with 3*45.75 or 137.25 cakes and cream puffs at first.(not in whole number)

Best wishes

[small]

Good morning tianzhu,


We also got 8U = 366, my DS said may be somebody ate the cake and puff..

[MathIzzzFun]

small:

Good morning tianzhu,


We also got 8U = 366, my DS said may be somebody ate the cake and puff..

good morning!

haha.. I think the question was likely adapted by changing only names of items - if the cakes and puffs are replaced by kg of flour and kg of sugar, then the answer will make sense

[YumYum]

Hi small,


Thank you for the 2 methods to derive the answers.

Your child is ahead of mine in practising the papers

have a good week-end!

[small]

U r welcome YumYum

[tianzhu]

insider:

deleted to avoid confusion.


Tireless Tianzhu, thank you!

Hi insider

Good Morning.

I am surprised you’re looking at the solutions because I understand you have grown up children.

Once again, thank you.

Best wishes

[homeworkmummy]

Hi, pls help with the following question and thanks in advance.


Xavier, Yew Ming and Zason bought a watch for their mother on her birthday. Xavier paid 1/4 of what Yew Ming and Zason paid. Yew Ming paid 1/5 of what Xavier and Zason paid. If Zason paid $56 more than Yew Ming, how much did the watch cost?