Q&A - PSLE Math

[YumYum]

Hi, I need help with these qns:


1) if Jeremy gave 15 stickers to Ramesh, he would have four times as many stickers as Ramesh. If Ramesh gave 5 stickers to Jeremy, the ratio of jeremys stickers to Ramesh’s stickers would be 14:1. How many stickers did Jeremy have?

2) four children, Wilson, Felicia, Darren and Annabel, sat for a math test and scored a total of 318 marks. If we take any 3 of their marks, we will get an average of 75, 78 and 81 respectively. Wilson and Darren scored the highest and the lowest respectively. Find the total score of Wilson and Darren.

(not sure by what "takevany 3 of their marks means…).

3) when mr gopal was 40 yrs old, his son, Kumar, was twice the age of his daughter, Rita. Mr gopal would be 3 times his son’s age when rita was 12 yrs old. How old would Mr gopal be when Rita was 20 yrs old?

Thanks

[MathIzzzFun]

YumYum:

Hi, I need help with these qns:


1) if Jeremy gave 15 stickers to Ramesh, he would have four times as many stickers as Ramesh. If Ramesh gave 5 stickers to Jeremy, the ratio of jeremys stickers to Ramesh's stickers would be 14:1. How many stickers did Jeremy have?

Thanks

Total number of stickers remain the same.

If Jeremy gave 15 stickers to Ramesh, Jeremy's stickers : Ramesh' s stickers = 4 : 1 --> 12u : 3u
If Ramesh gave 5 stickers to Jeremy, Jeremy's stickers : Ramesh's stickers = 14u : 1u

Ramesh: 3u - 1u = 15 + 5 = 20, 1u --> 10

Jeremy's stickers --> 12 x 10 + 15 = 135

cheers.

[MathIzzzFun]

YumYum:

Hi, I need help with these qns:


2) four children, Wilson, Felicia, Darren and Annabel, sat for a math test and scored a total of 318 marks. If we take any 3 of their marks, we will get an average of 75, 78 and 81 respectively. Wilson and Darren scored the highest and the lowest respectively. Find the total score of Wilson and Darren.

Thanks

75 x 3 = 225, 1st score --> 318 - 225 = 93
78 x 3 = 234, 2nd score --> 318 - 234 = 84
81 x 3 = 243, 3rd score --> 318 - 243 = 75
4th score --> 318 - 93 - 84 - 75 = 66

Wilson --> 93
Darren --> 66
Total --> 159

cheers.

[MathIzzzFun]

YumYum:

Hi, I need help with these qns:


3) when mr gopal was 40 yrs old, his son, Kumar, was twice the age of his daughter, Rita. Mr gopal would be 3 times his son's age when rita was 12 yrs old. How old would Mr gopal be when Rita was 20 yrs old?

Thanks

similar question here...

http://www.flickr.com/photos/62167097@N02/5679985631/in/photostream

Gopal --> 40
Rita --> 1 unit
Kumar --> 2 units (age difference between Rita and Kumar = 1unit)


Rita --> 12
Kumar --> 12 + 1 unit (age difference remains the same)
Gopal --> 36 + 3 units (age difference between Gopal and Kumar = 24 + 2 units)

so, when Gopal --> 40 = 2 units (Kumar's age) + 24 + 2 units
1 unit --> 4

Age difference between Gopal and Rita = 40 - 4 = 36
Rita --> 20
Gopal --> 56

cheers.

[imacsg]

Can anyone help me the below question?


Jack, Meili and Raj shared some 50 cent coins.
They each had an average of 28 coins.
The total amount of money that Jack and Meili had was $7 more than the total amount of Jack and Raj had.
If Raj’s amount was 4 time of Jack’s amount, how much more money did Meili have than Jack?

Thanks

[MathIzzzFun]

imacsg:

Can anyone help me the below question?


Jack, Meili and Raj shared some 50 cent coins.
They each had an average of 28 coins.
The total amount of money that Jack and Meili had was $7 more than the total amount of Jack and Raj had.
If Raj's amount was 4 time of Jack's amount, how much more money did Meili have than Jack?

Thanks

Question is not set properly .. answer is not a terminating decimal. It would be better if the last sentence reads \"If Raj's amount was 3 times of Jack's amount, how much more money did Meili have than Jack?\"

Total amount of money --> 28 x 3 x $0.50 = $ 42
Meiji had $7 more than Raj

Amount each has:
Jack --> 1 unit
Raj --> 4 units
Meiji --> 4 units + $7
Amount Meiji had more than Jack --> 3 units + $7

Total amount --> 9 units + $7 = $42
9 units --> $35
3 units --> $ 11 2/3
Amount Meiji had more than Jack --> $11 2/3 + $7 = $18 2/3

cheers.

[YumYum]

MathIzzzFun:

YumYum:

Hi, I need help with these qns:


3) when mr gopal was 40 yrs old, his son, Kumar, was twice the age of his daughter, Rita. Mr gopal would be 3 times his son's age when rita was 12 yrs old. How old would Mr gopal be when Rita was 20 yrs old?

Thanks

similar question here...

http://www.flickr.com/photos/62167097@N02/5679985631/in/photostream

Gopal --> 40
Rita --> 1 unit
Kumar --> 2 units (age difference between Rita and Kumar = 1unit)


Rita --> 12
Kumar --> 12 + 1 unit (age difference remains the same)
Gopal --> 36 + 3 units (age difference between Gopal and Kumar = 24 + 2 units)

so, when Gopal --> 40 = 2 units (Kumar's age) + 24 + 2 units
1 unit --> 4

Age difference between Gopal and Rita = 40 - 4 = 36
Rita --> 20
Gopal --> 56

cheers.

Dear MathIzzzFun, thank you for yr usual and prompt help :rahrah:

[imacsg]

Dear MathIzzzFun,


I also have the same ans, but find a bit odd, in fraction. So I think the question is not set properly.
Thank you for yr usual and prompt help.

[bndreve]

Hi, need help with the following question. Thanks.


Issac had some red and blue marbles in a container. First, he added in 22 red marbles and as a result, 40% of the marbles in the container were blue. Next, he added in another 180 blue marbles and as a result, 60% of the marbles were blue. Finally, he removed some red marbles such that the ratio of the remaining red marbles to the remaining blue marbles was 1:3.
a) How many red mables did he have at first?
b) How many red marbles did he remove?

[tianzhu]

bndreve:

Hi, need help with the following question. Thanks.


Issac had some red and blue marbles in a container. First, he added in 22 red marbles and as a result, 40% of the marbles in the container were blue. Next, he added in another 180 blue marbles and as a result, 60% of the marbles were blue. Finally, he removed some red marbles such that the ratio of the remaining red marbles to the remaining blue marbles was 1:3.
a) How many red mables did he have at first?
b) How many red marbles did he remove?

Hi

I've drawn more MD than necessary, once students understand the concept they may consodilate the steps.

Hope this helps.

Best wishes

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