Q&A - PSLE Math

[KP2]

Hi,

Could you please help me with this question?

Mr Johnson bought 1.5 times as many toy cars as toy trains. He spent $8456 altogether. A toy train costs $16 more than a toy car. The total cost of the toy trains was $616 less than the total cost of the toy cars. Find the cost of the toy car.

[MathIzzzFun]

KP2:

Hi,

Could you please help me with this question?

Mr Johnson bought 1.5 times as many toy cars as toy trains. He spent $8456 altogether. A toy train costs $16 more than a toy car. The total cost of the toy trains was $616 less than the total cost of the toy cars. Find the cost of the toy car.

total cost for the trains = $(8456-616)/2 = $ 3920
total cost for the toy cars = $8456 - $3920 = $4536

number of trains --> 2 units, cost of trains/unit --> $3920/2 = $1960
number of toy cars --> 3 units, cost of toy cars/unit --> $4536/3 = $1512

Number of cars/toy in 1 unit = ($1960-$1512)/$16 = 28

cost of 1 train --> $ 2960/28 = $70
cost of 1 toy car --> $1512/28 = $54

cheers.

[ozora]

Need guide in the following double if questions.

Q1. A team of students calculated their average score for their tests.
If anyone of them scored 5 points less, their average score would be 87.
If anyone of them scored 13 more points, their average score would be 90.
How many students are there?

Q2. A baker made some cookies.
If he packs a vanilla cookie with a choco cookie, there will be 60 choco cookies left.
If he packs every 2 vanilla cookies with 3 choco cookies, there will be 50 vanilla cookies left.
how many cookies did he make?
thanks

[tianzhu]

YumYum:

Hi, can someone pls help with these Qns:


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 18:55 and the ratio of Noel's red marbles to blue marbles became 7:20.
How many red marbles did Mary buy?

Hi

Please check with your source.

We could not get nice whole number as the answer.

Perhaps, it should be read as 18:85

The solution is based on the revised ratio of 18:85

Hope this helps

Best wishes

http://farm8.staticflickr.com/7456/8722620110_27aa90062c_z.jpg\">

[KP2]

:thankyou: MathIzzzFun

[fullhope]

Thanks Tianzhu for the answer.

[fullhope]

Thanks Tianzhu for the answer.

[YumYum]

Tianzhu, thks for yr help the Qn on the marbles, the ratio is indeed 18:85. My mistake in typing it out. Thanks :rahrah:

[smileplease]

Please help in this Q.


J and R are given some money each. If J and R spend $60 and $30 each day respectively, J will still have $600 when R has spent all his money. If J and R spend $30 and $60 each day respectively, J will still have $1500 when R has spent all his money.

a) How much is given to J at first?
b) If J and R spend $35 and $20 respectively, how much money would J have left when R has spent all his money?

Thank you…

[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