Q&A - PSLE Math

[2632parent]

On Sunday, Mrs Tan gave Devi and Susan some sweets. On Monday, Devi gave Susan 40%of her sweets. On Tuesday, after Susan gave 2/5 of her sweets to Devi both of them had the same number of sweets. If Susan had 112 more sweets than Devi at first, how many sweets did Devi have on Sunday. :thankyou:

[tianzhu]

superksmum:

Pls help!


Dave and Carl had 186 marbles altogether. Dave had 6 more marbles than Carl. In a game, Dave lost 25% as many marbles as the number of marbles Carl lost to Eng Hong. Dave was then left with twice as many marbles as Carl. How many marbles did Dave have after the game?

Thank you.

Hi

Due to time constraints, I’ll not be drawing the MD.

I’ll use Units and Parts as an illustration. You may draw the MD by replacing the Units and Parts with boxes.

Dave ------ 96
Carl ------- 90

Dave
Lost ------ 1 part
Left ------ 2 units

Carl
Lost ------ 4 parts
Left ------ 1 unit

Rearrange the MD, you’ll see 1 unit = 3 parts + 6

1 unit + 4 parts = 90 (Carl)
3 parts + 6 + 4 parts = 90
7 parts = 84
1 part = 12

96 – 12 = 84

Dave had 84 marbles left.

If you want to have a similar question for practice, you may have a go at this one.

Father gave Nicholas and Rachel $630 to buy some clothes. Nicholas was given $60 more than Rachel. At the shop, Nicholas spent twice as much as Rachel. Rachel was left 3 times as much money as Nicholas.How much did Nicholas spend?

Best wishes

[Winx5015]

thanks tianzhu

[superksmum]

Hi Tianzhu,

Thank you.

[Michaelia0816]

Ok thanks for checking my answer, Tianzhu!!!

[Michaelia0816]

2632parent:

On Sunday, Mrs Tan gave Devi and Susan some sweets. On Monday, Devi gave Susan 40%of her sweets. On Tuesday, after Susan gave 2/5 of her sweets to Devi both of them had the same number of sweets. If Susan had 112 more sweets than Devi at first, how many sweets did Devi have on Sunday. :thankyou:

I bet you have written it wrongly as Devi is 20% more than Susan at first!
I will write the answer in next posts!

[Michaelia0816]

100%-40%=60%

Monday:
Devi got 60% of sweets at first.
Susan got 40% of sweets at first.
2/5 of 60% is 24%
60%-24%=36%
40%+24%=64%
64%-36%=28%
28%-112 sweets
1%-4 sweets
100%-400 sweets
The answer is 400 sweets.

[Michaelia0816]

Wish u good luck in find the answer :xedfingers:

[Michaelia0816]

A) 100%+20%=120%

120%=120/100
120/100x$1.50=$1.80
B) 100%-25%=75%
75%= 75/100
75/100x500=375
C) 375x$1.80=$675
Now using the in front information to do D. It would be much easy.
500x$1.50=$750
675/750x100%=90%
100%-90%=10%
Decrease.
D)

[Michaelia0816]

Would it be better to draw model for understanding!