## Q&A - P5 Math

- Dragon Flame
- OrangeBelt
**Posts:**90**Joined:**Thu Oct 16,

### Re: Q&A - P5 Math

The ratio of the number of stickers Christopher had to the number of stickers Gene had was 1 : 3. After Christopher bought 5 more stickers and Gene bought 9 more stickers, the ratio became 2 : 5. How many more stickers had Gene than Christopher in the end ?

- Dragon Flame
- OrangeBelt
**Posts:**90**Joined:**Thu Oct 16,

### Re: Q&A - P5 Math

Alisha bought 12 pencils and 8 erasers. If she had bought these items at 25% discount, the amount of money she saved could buy another 6 more erasers at the usual price. The usual price of a pencil was $1.20. What was the usual price of the eraser ?

Pls help. Thank you very much !

Pls help. Thank you very much !

- alfretztay
- KiasuGrandMaster
**Posts:**1199**Joined:**Sun Sep 12,**Total Likes:**5

### Re: Q&A - P5 Math

… Canteen : Basketball CourtDragon Flame wrote:The ratio of pupils in the canteen is thrice the number of pupils at the basketball court. 4/9 of the pupils in the canteen are boys. There is an equal number of boys and girls at the basketball court. If there are 125 more boys in the canteen than at the basketball court, how many pupils are there in the canteen ?

......… 90u : 30u

......… B : G B : G

..... 40u : 50u 15u : 15u

40u – 15u = 25u

25u -> 125

1u -> 5

90u -> 450

Ans : 450 pupils

- alfretztay
- KiasuGrandMaster
**Posts:**1199**Joined:**Sun Sep 12,**Total Likes:**5

### Re: Q&A - P5 Math

... C : GDragon Flame wrote:The ratio of the number of stickers Christopher had to the number of stickers Gene had was 1 : 3. After Christopher bought 5 more stickers and Gene bought 9 more stickers, the ratio became 2 : 5. How many more stickers had Gene than Christopher in the end ?

... 1u : 3u

... +5 +9

... ----- -----

... 2p 5p

1u + 5 -> 2p

3u + 15 -> 6p

3u + 9 -> 5p

1p -> 6

2p -> 12

5p -> 30

30 - 12 = 18

Ans : 18 more stickers

Last edited by alfretztay on Thu Oct 23, 2014 1:11 pm, edited 1 time in total.

- alfretztay
- KiasuGrandMaster
**Posts:**1199**Joined:**Sun Sep 12,**Total Likes:**5

### Re: Q&A - P5 Math

Let the the usual price of the eraser be $p.Dragon Flame wrote:Alisha bought 12 pencils and 8 erasers. If she had bought these items at 25% discount, the amount of money she saved could buy another 6 more erasers at the usual price. The usual price of a pencil was $1.20. What was the usual price of the eraser ?

Pls help. Thank you very much !

12 x 1.20 = 14.40

25% of 14.40 = 3.60

3.60 + 0.25(8p) = 6p

4p -> 3.60

1p -> 0.90

Ans : $0.90

### Re: Q&A - P5 Math

Dragon Flame wrote:The ratio of pupils in the canteen is thrice the number of pupils at the basketball court. 4/9 of the pupils in the canteen are boys. There is an equal number of boys and girls at the basketball court. If there are 125 more boys in the canteen than at the basketball court, how many pupils are there in the canteen ?

### Re: Q&A - P5 Math

In a school hall, chairs were arranged in rows such that there were exactly 15 chairs in each row. For a performance, 7 more chairs were added into the school hall and all the chairs were rearranged. There were now exactly 11 chairs in each row and 9 more rows than before. How many chairs are there in the school hall for the performance?

Pls help. Thank you.

Pls help. Thank you.

### Re: Q&A - P5 Math

9x11=99bcmum wrote:In a school hall, chairs were arranged in rows such that there were exactly 15 chairs in each row. For a performance, 7 more chairs were added into the school hall and all the chairs were rearranged. There were now exactly 11 chairs in each row and 9 more rows than before. How many chairs are there in the school hall for the performance?

Pls help. Thank you.

99-7=92

15-11=4

92/4=23(rows)

Total chairs-->23x15+7=352

### Re: Q&A - P5 Math

You get 92 chairs by removing (15 - 11) = 4 chairs from each original row.

92 / 4 = 23 gives you the number of original rows.

92 / 4 = 23 gives you the number of original rows.