## Q&A - PSLE Math

### Re: Q&A - PSLE Math

First, you have to find the lowest common multiple of the two denominators of the fractions, which is 7 and 9. So, the LCM is 21. Now, list out the multiples of 21 below 50, which will give you only 21 and 42. Now, you try both numbers.leo_mums wrote:There were fewer than 50 exercise books left at a school bookshop on Monday.

On Tuesday, 1/7 of the exercise books were sold.

On Wednesday, one book fewer than 4/9 of the remaining exercise books were sold.

On Thursday, 2 books more than 3/7 of the remaining exercise books were sold.

How many exercise books did the bookshop have on Monday?

21:

21*6/7=18

18*5/9=10

10+1=11

11*4/7=6 2/7

6 2/7-2=4 2/7

So, that means that you can't use 21.

42:

42*6/7=36

36*5/9=20

20+1=21

21*4/7=12

12-2=10

Ans:42

### Re: Q&A - PSLE Math

TheSolver!TheSolver wrote:First, you have to find the lowest common multiple of the two denominators of the fractions, which is 7 and 9. So, the LCM is 21. Now, list out the multiples of 21 below 50, which will give you only 21 and 42. Now, you try both numbers.leo_mums wrote:There were fewer than 50 exercise books left at a school bookshop on Monday.

On Tuesday, 1/7 of the exercise books were sold.

On Wednesday, one book fewer than 4/9 of the remaining exercise books were sold.

On Thursday, 2 books more than 3/7 of the remaining exercise books were sold.

How many exercise books did the bookshop have on Monday?

21:

21*6/7=18

18*5/9=10

10+1=11

11*4/7=6 2/7

6 2/7-2=4 2/7

So, that means that you can't use 21.

42:

42*6/7=36

36*5/9=20

20+1=21

21*4/7=12

12-2=10

Ans:42

### Re: Q&A - PSLE Math

Hi all,

THis question has been asked in the forum before..However, there wasnt a detailed explanation to this question... Would some kind soul please help to solve this ..THanks in advance!

THis question has been asked in the forum before..However, there wasnt a detailed explanation to this question... Would some kind soul please help to solve this ..THanks in advance!

**If Kenny gives 18 marbles to Andrew, he will have thrice as many marbles as Andrew. If Andrew gives 12 marbles to kenny, he will have 1/9 of the number of marbles that kenny has. How many marbles does Kenny have at first?**### Re: Q&A - PSLE Math

Hi all,

Not too sure how to solve these 2 questions.. Please help.. THanks so much in advance.

Not too sure how to solve these 2 questions.. Please help.. THanks so much in advance.

**1: Mrs Low bought a total of 20 hens and geese for $126.Each goose cost $2 more than a hen. How much did she pay for each goose if she bought 6 fewer hens than geese?**

2: Andrew , Annie and Ravin opened a bank account each in January 2008.Every month, Andrew, Annie and Ravin deposited $20,$30 and $45 into their bank accounts respectively. IF Annie's account was $900 after a few months,

a) How much longer did Andrew take than Annie to top up his savings to $900?

b)How much would Ravin have when Andrew had topped up to $900?2: Andrew , Annie and Ravin opened a bank account each in January 2008.Every month, Andrew, Annie and Ravin deposited $20,$30 and $45 into their bank accounts respectively. IF Annie's account was $900 after a few months,

a) How much longer did Andrew take than Annie to top up his savings to $900?

b)How much would Ravin have when Andrew had topped up to $900?

### Re: Q&A - PSLE Math

After 3 hrs, Mr Rahu left 3 hrs to go, i.e he traveled half of his distance. Let the total Distance for Mr Raju be 2R.EC72 wrote:Mr Ali and Mr Raju started driving to town A at the same time.

Mr Raju took 6 hours to reach town a while Mr Ali took 9 hours to reach town A.

After 3 hours, both men were left with the same distance to complete.

Find the ratio of the total distance travelled by Mr Raju to that travelled by Mr Ali to reach town A if the both of them drove at a constant speed.

After 3 hrs, Ali have traveled 1/3 of his distance, since he still have 6 hours to go.Let total distance for Ali be 3A.

The remaining distance for Mr Raju is 1R and Ali is 2A and they are equal.

1R = 2A

Total distance for Mr Raju = 2R = 4A ...... (Since 1R=2A)

Total distance for Ali = 3A

Distance Raju : Ali -> 4 : 3

### Re: Q&A - PSLE Math

Ender!Ender wrote:After 3 hrs, Mr Rahu left 3 hrs to go, i.e he traveled half of his distance. Let the total Distance for Mr Raju be 2R.EC72 wrote:Mr Ali and Mr Raju started driving to town A at the same time.

Mr Raju took 6 hours to reach town a while Mr Ali took 9 hours to reach town A.

After 3 hours, both men were left with the same distance to complete.

Find the ratio of the total distance travelled by Mr Raju to that travelled by Mr Ali to reach town A if the both of them drove at a constant speed.

After 3 hrs, Ali have traveled 1/3 of his distance, since he still have 6 hours to go.Let total distance for Ali be 3A.

The remaining distance for Mr Raju is 1R and Ali is 2A and they are equal.

1R = 2A

Total distance for Mr Raju = 2R = 4A ...... (Since 1R=2A)

Total distance for Ali = 3A

Distance Raju : Ali -> 4 : 3

### Re: Q&A - PSLE Math

TheSolver, how is it the LCM for 7 and 9 is 21?TheSolver wrote:First, you have to find the lowest common multiple of the two denominators of the fractions, which is 7 and 9. So, the LCM is 21. Now, list out the multiples of 21 below 50, which will give you only 21 and 42. Now, you try both numbers.leo_mums wrote:There were fewer than 50 exercise books left at a school bookshop on Monday.

On Tuesday, 1/7 of the exercise books were sold.

On Wednesday, one book fewer than 4/9 of the remaining exercise books were sold.

On Thursday, 2 books more than 3/7 of the remaining exercise books were sold.

How many exercise books did the bookshop have on Monday?

21:

21*6/7=18

18*5/9=10

10+1=11

11*4/7=6 2/7

6 2/7-2=4 2/7

So, that means that you can't use 21.

42:

42*6/7=36

36*5/9=20

20+1=21

21*4/7=12

12-2=10

Ans:42

- berryspice
- KiasuNewbie
**Posts:**2**Joined:**Mon Aug 10,

### Re: Q&A - PSLE Math

http://www.kiasuparents.com/kiasu/forum ... 3#p1540853berryspice wrote:

Hi,

Need help to solve this question.

Thanks in advance.