Q&A - PSLE Math

[tianzhu]

Hi moderators


Please help to delete.

Best wishes

[sokk]

tianzhu:

sokk:

I need help for this question.


Rita and Molly shared some stickers between them.
If Rita gives 15 of her stickers to Molly, Molly will have thrice as many stickers as Molly.
If Molly gives 15 of her stickers to Rita, Rita will have twice as many stickers as Molly.How many stickers does each of them have?



Thanks!!

Hi

Perhaps, it should be read as “If Molly gives 15 of her stickers to Rita, Molly will have twice as many stickers as Rita.

Best wishes

Hi,
Yes, hehe, it was my typo error. Whole morning been confused by this Molly Rita question. hahaha...
I have interpreted wrongly, thinking that after Rita gives Molly 15 stickers , Molly proceeds to give Rita 15 stickers. Hence I arrived at the answer
Molly 12 stickers and Rita 24 stickers.


Hi MathsHub
Thanks for the help!

[sokk]

Maths Hub:

sokk:

Hi,
Thanks for the quick reply. But when I try to work out the story using Rita 33 and Molly 39 at first, I can't seems to get Rita having twice as many as Molly .

At first
Rita 33 Molly 39

after Rita gives Molly 15
Rita 18 , Molly 54
(Molly has thrice as many as Rita)

after Molly gives Rita 15
Rita 33 , Molly 39
(I can't arrive at Molly having twice..)

Did I interpret the question wrongly??
Please help! getting confuse....

Hi,

After Molly give Rita 15
Rita 48, Molly 24
(Rita is twice Molly, not the other way round)

Hope that helps.

Hi Maths Hub,
Thank you very much for your help! I understand now.

[RelaxedMum]

iCreative Math:

Yum Yum, your question below:-


1) Mary bought some red marbles and have half to Noel.
Noel bought some blue marbles and gave half to Mary.
Mary lost 16 red marbles and Noel lost 55 blue marbles.
The ratio of Mary's red marbles to blue marbles became 18:85 and the ratio of Noel's red marbles to blue marbles became 7:20.
How many red marbles did Mary buy?

is adapted from the 2009 PSLE question with changes to the numbers and the resultant ratios but they are essentially similar questions.

I have posted the explanation of the solution to the 2009 PSLE question in YouTube (see the link below).

I hope the verbal explanation will be helpful for your child to understand the solution to this sort of questions.

http://www.youtube.com/watch?v=epaXFwd5j_0

Best Regards,

iCreative Math

Many thanks for the explanation

[superksmum]

Hi, can someone please help:


Mrs Tan had 130 apples and oranges. After she sold 2/3 of the apples and 2/5 of the oranges, she had 36 more apples than oranges left. How many fruits had she left in all?

[superksmum]

Hi, another question:

Aaron, Betsy, Charmaine and Deon share the cost of a friend’s birthday present equally. As Aaron only had $2 with him, the rest of his share was paid by his friends first. The ratio of the total amount of money Betsy and Charmaine paid to that Deon paid is 7:5. If Aaron returned $15 to Deon, find the cost of the present.

Thanks

[MathIzzzFun]

superksmum:

Hi, another question:

Aaron, Betsy, Charmaine and Deon share the cost of a friend's birthday present equally. As Aaron only had $2 with him, the rest of his share was paid by his friends first. The ratio of the total amount of money Betsy and Charmaine paid to that Deon paid is 7:5. If Aaron returned $15 to Deon, find the cost of the present.

Thanks

amount paid by Betsy & Charmaine : Deon --> 7u : 5u -- total 12u

total cost of present --> 12u + $2
each person --> 3u + $0.50

Aaron's share paid by Deon --> 5u - 3u - $0.50 2u - $0.50

2u - $0.50 = $15
1u --> $7.75

Cost of present --> 12 x $7.75 + $2 = $ 95

cheers.

[iamproudparents]

hello guys,


need some advice on these questions. thanks and have a great weekend.

1) jasmine put 19 stickers in packet A, 24 stickers in packet B, 15 stickers in packet C and 80 stickers in packet D. Nora added an equal number of stickers into each of the packets. As a result, packet D contained the same number of stickers as the total number of stickers in packets A, B and C. How many stickers were there in packet D in the end?

2) Truck A and Truck B started traveling from Point X on a road but in opposite direction. After 2 hours, they were 292 km apart. Truck B’s average speed was 10km/h slower than Truck A’s. What was Truck B’s average speed?

3) A blouse cost 4/5 as much as a dress. Serena spent 3/8 of her money on 3 blouses. She also bought 2 dresses. What fraction of her money did she spend altogether?

4) 800 more females than males went for a workshop on the first day. On the second day, the number of females decreased by 10% while the number of males increased by 40%. 3641 people went to the workshop on the second day

a) How many females were there at the workshop on the second day?
b) If each participant for the workshop had to pay $8, how much money was collected from the workshop on the first day?

5) At 1030 hr, Ben started traveling from Town A towards Town B. At the same time, Chandra started traveling from Town B towards Town A. Town A and Town B were 195 km apart. Ben Traveled at an average speed that was 15 km/h more than Chandra’s average speed. They met each other at 1330 hr. What was Ben’s average speed?

6) Steven gave 40% of his salary to his parents. He used 60% of the remaining money to pay his bills and he saved the rest. If the amount he gave to his parents was $800 more than the amount he saved, how much was Steven’s salary?

cheers!

[Mary Joy]

Hello everyone,


Please help me with this question.

Ken and Peter went shopping with a total of $90.Ken spent twice as much as Peter.Ken had spent $5 more than the amount that he had left.In the end,Peter had thrice as much money left as Ken.

A) How much money did Peter spend?
B)How much money did Ken have at first?

[MathIzzzFun]

Mary Joy:

Hello everyone,


Please help me with this question.

Ken and Peter went shopping with a total of $90.Ken spent twice as much as Peter.Ken had spent $5 more than the amount that he had left.In the end,Peter had thrice as much money left as Ken.

A) How much money did Peter spend?
B)How much money did Ken have at first?

Left, Ken : Peter --> 2u : 6u --- Left, total --> 8u
Spent, Ken : Peter --> 2u + $5 : 1u + $2.50 ---- Spent, total --> 3u + $7.50

Total amount of money --> 11u + $7.5 = $90
1u --> $7.50

a) amount spent by Peter --> $7.50 + $ 2.50 = $10
b) Ken's money at first --> 4 x $ 7.50 + $5 = $35

cheers.