Q&A - PSLE Math

[tianzhu]

Suz855:

It's a recent school prelim qn, did you use guess n check? Can show how you work out one of the multiple answer, thks

Hi

From the way the question is crafted, it gives rise to multiple answers.

Why, because the price of a burger varies according to the price of 5 fries + 10.5.Hence, you’ll get different amount of pocket money.

If you modify the question, then you can get one answer.

A can buy 10 fries n 4 burgers using all his money. If he decided to buy 5fries n 5 burgers, he will be short of $10.50.Given that the price of 1 burger is $13, find A's pocket money.

A can buy 10 fries n 4 burgers using all his money. If he decided to buy 5fries n 5 burgers, he will be short of $10.50.Given that the price of 10 fries is $5, find A's pocket money.

Best wishes

[Suz855]

Thks TZ, think the school wants the students to think out of the box.

[fightingmom]

Hi,


Can someone help with the following question:

http://i47.tinypic.com/c2lxx.jpg\">

TIA !

[tianzhu]

fightingmom:

Hi,


Can someone help with the following question:

http://i47.tinypic.com/c2lxx.jpg\">

TIA !

Hi

This question has been discussed earlier.

Best wishes

http://farm5.staticflickr.com/4133/4975546078_eaed16dcca_z.jpg\">

[fightingmom]

tianzhu:

fightingmom:

Hi,


Can someone help with the following question:

http://i47.tinypic.com/c2lxx.jpg\">

TIA !

Hi

This question has been discussed earlier.

Best wishes

http://farm5.staticflickr.com/4133/4975546078_eaed16dcca_z.jpg\">

:thankyou: tianzhu for your prompt reply !

[peggy]

Please assist with this.


There are more pupils in school A than school B. 30%of the pupils in school A is 45 more than 40% the pupils in school B. If 10% of the pupils in school A leaves to join school B, there will be 200 more pupils in school A than in school B.
a. How many pupils are there in school B?
B. How many percent less pupils are there in school B than school A?
Leave your answer as a fraction in the simplest form.

Thanks!

[tianzhu]

peggy:

Please assist with this.


There are more pupils in school A than school B. 30%of the pupils in school A is 45 more than 40% the pupils in school B. If 10% of the pupils in school A leaves to join school B, there will be 200 more pupils in school A than in school B.
a. How many pupils are there in school B?
B. How many percent less pupils are there in school B than school A?
Leave your answer as a fraction in the simplest form.

Thanks!

Hi

You may work with MD or units.

One possible way.

30% ------- 3/10 ------- 6/20

40% ------- 2/5 -------- 6/15

A common multiple of 2 and 3 is 6.

30% of the pupils in school A is 45 more than 40% the pupils in school B.

6 units ------- 6 units + 45

2 units -------- 2 units + 15

At first

School A ------- 20 units + 150

School B ------- 15 units

If 10% of the pupils in school A leaves to join school B, there will be 200 more pupils in school A than in school B.

In the end

School A ------- 18 units + 135

School B ------- 17 units + 15

18 units + 135 ------- 17 units + 15 + 200

1 unit ------- 80

Number of pupils@B ------- 15*80 ------- 1200

Number of pupils@A -------- 20*80 + 150 --------- 1750

1750 – 1200 -------- 550

550/1750*100% ------- 31 3/7%

Best wishes

[peggy]

Thanks, Tianzhu!

[kwcllf]

An Express train travels from Town A to Town B. A Normal train travels from Town B to Town A at the same time. When the two trains meet, the Express train has travelled 105km more than the Normal train. The two trains reached their destination in 6 hours and 10 hours respectively. What is the distance between the two towns?


Thanks.

[tianzhu]

kwcllf:

An Express train travels from Town A to Town B. A Normal train travels from Town B to Town A at the same time. When the two trains meet, the Express train has travelled 105km more than the Normal train. The two trains reached their destination in 6 hours and 10 hours respectively. What is the distance between the two towns?


Thanks.

Hi

For Speed questions, it’s useful to begin with a simple diagram.

A neat way is to use inverse proportion.

Time taken by express train: Time taken by normal train -------- 6:10 ------- 3:5

Distance covered by express train: Distance covered by normal train ------- 5:3

5-3 ------- 2

2 units ------- 105

1 unit ------- 52.5

Distance between two towns -------- 8*52.5 -------- 420 km

Best wishes