Q&A - PSLE Math

[Fly2high]

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

[alfretztay]

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

I would solve the above question as follows :
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.

[Fly2high]

Thanks very much Alfretztay !!

[ozora]

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 = 176

4u + 1.5u =176
u= 32

Total people at noon time = 5u + 3u = 8u = 256#

thanks

[doraemo]

please help :

1) The ratio of the number of marbles May, Teddy and Sam had was 3:5:2. During a game, May lost half of her marbles to Teddy. Teddy lost 20 marbles to Sam who then had 3 times the number of marbles May had at the end of the game.
a) What was the percentage increase in the number of marbles Sam had at the end of the game?
b) How many marbles did Teddy have at the end of the game?


2) At a fun-raising event, 60% of the people were male and the rest were female. 20% of the female left the event in the afternoon.
In the evening, after 33 male and 35 female left the event, 75% of the people at the event were male.
a) What percentage of the people left the event in the afternoon?
b) How many people were there at the start of the fun raising event?

[ChiefKiasu]

When posting questions, please post only 1 question per post, and not multiple in 1 post. It makes it easier to get answers for your questions.

[Ender]

vvv
A: 1702574
Subject: Math
Level: P6
Tags: Ratio, Percentage, u
Source:
^^^
Question 1
M :T : S => 3u : 5u : 2u

After the game
M : T : S => 1.5u : 6.5u-20 : 2u + 20

We know in the end Sam is 3 times of May
2u + 20 = 3X(1.5u)
2u + 20 = 4.5u
2.5u = 20
u = 8

a) before the game Sam =2u = 16
After the game, he gain 20 marbles from Teddy
Percentage increase = 20/16 X100 = 125% ##

b) in the end Teddy has 6.5u-20 = 32 marbles ##

Question 2,
Please see the link. Already answered,
http://www.kiasuparents.com/kiasu/forum ... 6#p1682926

[BigDevil]

Need some guide on the following questions

Thanks

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 = 176

4u + 1.5u =176
u= 32

Total people at noon time = 5u + 3u = 8u = 256#

The question says:
"Ten minutes later, 1/5 of the males and 1/2 of the females LEFT the bus terminal.
Twenty minutes later, when another 23 males and 32 females CAME to the bus terminal, there were a total of 121 people..."

I believe at 12:10, there should be
Total = 121 - 23 - 32 = 66

4u + 1.5u = 66
1u = 12

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

[Ender]

Need some guide on the following questions

Thanks

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 = 176

4u + 1.5u =176
u= 32

Total people at noon time = 5u + 3u = 8u = 256#

The question says:
"Ten minutes later, 1/5 of the males and 1/2 of the females LEFT the bus terminal.
Twenty minutes later, when another 23 males and 32 females CAME to the bus terminal, there were a total of 121 people..."

I believe at 12:10, there should be
Total = 121 - 23 - 32 = 66

4u + 1.5u = 66
1u = 12

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

Right, Thanks. I misread the the question. The answer as above by Bigdevil.

[alfretztay]

Thanks very much Alfretztay !!

You are most welcome, Fly2high !!