Q&A - PSLE Math

[MathIzzzFun]

Easy-going:

Please help with this question

Singapore Chinese Girls' SA 1 2012
Qn 16
Ivy bought some marbles and gave half of them to Joan. Joan bought some stamps and gave half of them to Ivy. Ivy gave away 8 stamps and Joan gave away 12 marbles. The ratio of the number of stamps to the number of marbles Ivy had left then became 1:5 and the ratio of the number of stamps to the number of marbles Joan had left became 1:3. How many stamps did Joan buy?
:thankyou:

similar question here - http://www.flickr.com/photos/mathizzzfun/6943541872/in/set-72157632928079102

cheers.

[lee tong fong]

Hi, can anyone help me in this question


1)The number of chickens in farm A and Farm B are in the ratio 9:1.
Farm A sold a certain number of chickens and Farm B sold 2/3 of its chickens.
As a result, both Farm A and Farm B each had 209 chickens left.

(a) How many chickens were sold by the 2 Farm in all?
(b) What percentage of farm A’s chickens wre sold?

Thanks you

[lee tong fong]

Hi, can anyone help me with another question


(2) Joey has some red and blue beads.
If she buys another 15 red beads, the percentage of the red beads she has become 30%.
If she gives away 20 blue beads, the percentage of the blue beads she has becomes 76%.
However many red beads and blue beads do Joey have?

Thanks you again

[lee tong fong]

Hi, can anyone help me with another question


(3) To make a fruit cake, Mrs Lim used 90% strawberry and 10% mango.
The cost of the mangoes was 1.5 times that of the strawberries.
She spent $6.30 in all for the strawberries and mangoes
How much more would it cost her if she uses 40% strawbeey and 60% mango?

Thanks you again

[lee tong fong]

Hi, can anyone help me with another question


(4) Shaun and Chin Hong cycled along the same route from Point A to Point B
Shuan Cycled at the average speed of 20km/h and he was 4.5km ahead of Chin Hong when Chin Hong reached the half-way mark.
If Shuan reached Point B at 11:20am, what time would Chin Hong reach Point B?

Thanks you again

[lee tong fong]

Hi, can anyone help me with another question


(5) Peanut butter sandwiches and egg sandwiches are put on 2 plates, X and Y, such that there are equal number of sandwiches on each plate.
The ratio of the number of peanut butter sanswiches on plates x to the number of the peanut butter sanswiches on plates Y is 5:4.
The ratio of the number of egg sanswiches on plates x to the number of the egg sanswiches on plates Y is 3:5.
Find the ratio of the number of peanut butter sandwices on plates Y to the number of egg sandwiches on plate X.

Thanks you again

[lee tong fong]

Hi, can anyone help me with another question


(6) A total of 84 girls and 231 boys wre involved in a CIP programmeto clean up a section of the beach.
(a) Find the greatest number of groups that can be formed so that all the boys and girls are distributed equally among all the groups.
(b) What is the the total number of children in each group?

Thanks you again

[PapayaDad]

lee tong fong:

Hi, can anyone help me in this question


1)The number of chickens in farm A and Farm B are in the ratio 9:1.
Farm A sold a certain number of chickens and Farm B sold 2/3 of its chickens.
As a result, both Farm A and Farm B each had 209 chickens left.

(a) How many chickens were sold by the 2 Farm in all?
(b) What percentage of farm A's chickens wre sold?

Thanks you

Farm B sold 2/3 ; so remaining 1/3 which is 209
So initially have 209 x 3 = 627
Sold is 209 x 2 = 418

So farm A initially have 627 x 9 = 5643
inthe end have 209
Sold is 5643 - 209 = 5434

Total sold is 418 + 5434 = 5852

[PapayaDad]

lee tong fong:

Hi, can anyone help me with another question


(6) A total of 84 girls and 231 boys wre involved in a CIP programmeto clean up a section of the beach.
(a) Find the greatest number of groups that can be formed so that all the boys and girls are distributed equally among all the groups.
(b) What is the the total number of children in each group?

Thanks you again

84/2 = 42
42/3 = 14
14/2 = 7

check 231/7 = 33

Answer :
7 groups
Each group have 84/7=12 girls ; and 231/7=33 boys
Each group have 12 + 33 = 45 children

[PapayaDad]

lee tong fong:

Hi, can anyone help me with another question


(3) To make a fruit cake, Mrs Lim used 90% strawberry and 10% mango.
The cost of the mangoes was 1.5 times that of the strawberries.
She spent $6.30 in all for the strawberries and mangoes
How much more would it cost her if she uses 40% strawbeey and 60% mango?

Thanks you again

The cost of the mangoes was 1.5 times that of the strawberries.
interms of cost
1m=1.5s
10m=15s
90s : 15s
6s:1s
7s = 630
s = 90
m = 135

4s=360
6m=810
total=1170

1170 - 630 = 540