## Q&A - PSLE Math

- questionable_i
- BrownBelt
**Posts:**535**Joined:**Sat Oct 10,**Total Likes:**1

### Re: Q&A - PSLE Math

Can anyone help me with this question. Thank you.

http://i.imgur.com/itWcrNI.jpg

http://i.imgur.com/itWcrNI.jpg

### Re: Q&A - PSLE Math

Using AB as the base of the triangle ABC., the height of the triangle ABC will be 4cm.questionable_i wrote:Can anyone help me with this question. Thank you.

http://i.imgur.com/itWcrNI.jpg

AB = 5cm

Your can find triangle ABC with the above information of base and height.

Shaded area is half of triangle ABC.

### A Mathlympics Question

4 men and 4 women are to be seated at round table for dinner.If the men and women take alternate seats, how many arrangements are possible?

### Re: A Mathlympics Question

So there are 8 chairs.ksraja69 wrote:4 men and 4 women are to be seated at round table for dinner.If the men and women take alternate seats, how many arrangements are possible?

Chair 1: 8 possible combinations. Any of the men and women can take this chair.

Chair 2: 4 possible combinations. Has to be opposite gender of person taking chair 1

Chair 3: 3 possible combinations. Has to be same gender as chair 1, and now left only 3 choices.

Chair 4: 3 possible combinations. Has to be same gender as chair 2, and now left with 3 choices.

Chair 5: 2 possible combinations. Has to be same gender as chair 1 and 3, now left with 2 choices

Chair 6: 2 possible combinations. Has to be same gender as chair 2 and 4, now left with 2 choices

Chair 7: 1 choice, has to be same gender as chair 1, 3, 5

Chair 8: 1 choice, has to be same gender as chair 2, 4, 6

Total possible combination 8 X 4 X 3 X 3 X 2 X 2 X 1 X 1 = 1152

### Re: Q&A - PSLE Math

vvv

A: 1702339

Subject: Math

Level: P6

Tags: Ratio, Fraction, u

Source:

^^^

Let male be 5u and female be 3u at noon

After 10 minutes, 1/5 of male (1u) and 1/2 of female(1.5u) left

male =4u

female = 1.5u

Total number of people during the 10 minutes after noon.

Total = 121 - 23 - 32 = 66

4u + 1.5u =66

u= 12

Total people at noon time = 5u + 3u = 8u = 96#

Edit note: Amendment in red as pointed out by BigDevil.

A: 1702339

Subject: Math

Level: P6

Tags: Ratio, Fraction, u

Source:

^^^

Let male be 5u and female be 3u at noon

After 10 minutes, 1/5 of male (1u) and 1/2 of female(1.5u) left

male =4u

female = 1.5u

Total number of people during the 10 minutes after noon.

Total = 121 - 23 - 32 = 66

4u + 1.5u =66

u= 12

Total people at noon time = 5u + 3u = 8u = 96#

Edit note: Amendment in red as pointed out by BigDevil.

Last edited by Ender on Mon Jul 25, 2016 11:05 am, edited 2 times in total.

### Re: Q&A - PSLE Math

Hi pls help on the below

There are 8 more adults in swimming class A than swimming class B . If 8 men leave swimming class A, 1/3 of the adults

In swimming class A will be men . If 10 women leave swimming class B , the ratio of men to women in swimming class B

Will become 2:3 . Given that the ratio of the total number of men to women in both swimming

Classes is 3:5, how many adults are there in swimming class A ?

Thanks very much !

Fly2high

There are 8 more adults in swimming class A than swimming class B . If 8 men leave swimming class A, 1/3 of the adults

In swimming class A will be men . If 10 women leave swimming class B , the ratio of men to women in swimming class B

Will become 2:3 . Given that the ratio of the total number of men to women in both swimming

Classes is 3:5, how many adults are there in swimming class A ?

Thanks very much !

Fly2high

### Re: Q&A - PSLE Math

Hi pls help on the below

There are 8 more adults in swimming class A than swimming class B . If 8 men leave swimming class A, 1/3 of the adults

In swimming class A will be men . If 10 women leave swimming class B , the ratio of men to women in swimming class B

Will become 2:3 . Given that the ratio of the total number of men to women in both swimming

Classes is 3:5, how many adults are there in swimming class A ?

Thanks very much !

Fly2high

There are 8 more adults in swimming class A than swimming class B . If 8 men leave swimming class A, 1/3 of the adults

In swimming class A will be men . If 10 women leave swimming class B , the ratio of men to women in swimming class B

Will become 2:3 . Given that the ratio of the total number of men to women in both swimming

Classes is 3:5, how many adults are there in swimming class A ?

Thanks very much !

Fly2high

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

### Re: Q&A - PSLE Math

I would solve the above question as follows :Fly2high wrote:Hi pls help on the below

There are 8 more adults in swimming class A than swimming class B . If 8 men leave swimming class A, 1/3 of the adults

In swimming class A will be men . If 10 women leave swimming class B , the ratio of men to women in swimming class B

Will become 2:3 . Given that the ratio of the total number of men to women in both swimming

Classes is 3:5, how many adults are there in swimming class A ?

Thanks very much !

Fly2high

For class A,

men : women

1u + 8 : 2u

For class B,

men : women

2p : 3p + 10

1u + 8 + 2u – (2p + 3p + 10) = 8

3u ——- 5p + 10

[(1u + 8) + 2p] x 5 = [2u + (3p + 10)] x 3

5u + 40 + 10p = 6u + 9p + 30

1u ——- 10 + 1p

3(10 + 1p) ——- 5p + 10

2p ——- 20

1p ——- 20/2 = 10

1u ——- 10 + 10 = 20

1u + 8 + 2u ——- 3 x 20 + 8 = 68

Ans : 68 adults.