## Q&A - PSLE Math

### Re: Q&A - PSLE Math

[/quote]

3)After 30 mins, John has a head start of 20 X 0.5 = 10km

Relative speed, = 40 - 10 = 30km/h

Time taken to close up 10km gap = 10/30 = 1/3hours or 20 minutes##[/quote]

Hi Ender,

Why is the relative speed 40-10, is it not 40-20?

not very familiar with the concept of relative speed..

3)After 30 mins, John has a head start of 20 X 0.5 = 10km

Relative speed, = 40 - 10 = 30km/h

Time taken to close up 10km gap = 10/30 = 1/3hours or 20 minutes##[/quote]

Hi Ender,

Why is the relative speed 40-10, is it not 40-20?

not very familiar with the concept of relative speed..

### Re: Q&A - PSLE Math

You are right.. My careless mistake, it's should be 40-20 ..mum2b wrote:Hi Ender,3)After 30 mins, John has a head start of 20 X 0.5 = 10km

Relative speed, = 40 - 10 = 30km/h

Time taken to close up 10km gap = 10/30 = 1/3hours or 20 minutes##

Why is the relative speed 40-10, is it not 40-20?

not very familiar with the concept of relative speed..

So the answer will be 30 mins now..

I made the necessary amends on the main post.

Last edited by Ender on Tue Jun 21, 2016 4:44 pm, edited 1 time in total.

### Re: Q&A - PSLE Math

$3600 translates to 360 pieces of $10 notesquestionable_i wrote:Can anyone help me with these questions. Thank you.

Code: Select all

```
H : J
2 : 3
-360 +360
1 : 6
```

3u + 360 = 6p --(2)

(1) X 6,

12u - 2160 = 6p

3u +360 = 12u -2160

9u = 2520

u = 280

2u -360 = p

p = 560-360 = 200

In the end, H has 1p = 200 pieces of $10, =>value = $2000

J has 3u of $2notes=> 840 notes, Value = $1680.

Total J has in the end = 1680 + 3600 = $5280

The difference between what they left = $5280 - $2000 = $3280 ###

### Re: Q&A - PSLE Math

100C + 100T = 700 ---(1)questionable_i wrote:Can anyone help me with these questions. Thank you.

30C + 54T = 282 ----(2)

(2) X 100/30

100C + 180T = 940 -- (3)

(3) - (1)

80T = 240

T = 3

100C + 300 = 700

100C = 400

C = 4

Tables left = 54T = 54(3) = 162

Chairs left = 30C = 30(4) = 120

Difference betweent leftover tables and chairs = 162-120=42 ##

### Re: Q&A - PSLE Math

http://www.kiasuparents.com/kiasu/forum ... 7#p1489267questionable_i wrote:Can anyone help me with these questions. Thank you.

- PSLEstress
- YellowBelt
**Posts:**20**Joined:**Wed Jun 08,

### Re: Q&A - PSLE Math

vvv

Q: 1691718

Subject: Math

Level: P6

Tags: Ratios

Source: ???

^^^

Got a question.

There are some red and blue beads in a box.

If 5 red beads are removed, the ratio of the number of remaining red beads to blue beads is 1:6.

If 8 blue beads instead of 5 red beads are removed, the ratio of the number of red beads to the number of remaining blue beads is 1:4.

How many beads are there in the box?

Thank you.

Q: 1691718

Subject: Math

Level: P6

Tags: Ratios

Source: ???

^^^

Got a question.

There are some red and blue beads in a box.

If 5 red beads are removed, the ratio of the number of remaining red beads to blue beads is 1:6.

If 8 blue beads instead of 5 red beads are removed, the ratio of the number of red beads to the number of remaining blue beads is 1:4.

How many beads are there in the box?

Thank you.

### Re: Q&A - PSLE Math

vvv

A: 1691718

Subject: Math

Level: P6

Tags: Ratios

Source: ???

^^^

Note : R = 1u, and B = 6p

Form the equantion

R - 5 = 1p => 1u - 5 = 1p --(1)

B - 8 = 4u => 6p - 8 = 4u --(2)

Substitute (1) into (2)

6(1u - 5) - 8 = 4u

6u - 30 - 8 = 4u

2u = 38

u = 19

p = u-5 = 14

Red = 19,

Blue = 6p = 84

Total beads = 19 + 84 = 103 ###

A: 1691718

Subject: Math

Level: P6

Tags: Ratios

Source: ???

^^^

Code: Select all

```
R : B R : B
-5 -8
1p : 6p 1u : 4u
```

Form the equantion

R - 5 = 1p => 1u - 5 = 1p --(1)

B - 8 = 4u => 6p - 8 = 4u --(2)

Substitute (1) into (2)

6(1u - 5) - 8 = 4u

6u - 30 - 8 = 4u

2u = 38

u = 19

p = u-5 = 14

Red = 19,

Blue = 6p = 84

Total beads = 19 + 84 = 103 ###

### PSLE Math

vvv

Q: 1692365

Subject: Math

Level: P6

Tags: Ratios

Source: ???

^^^

Please help:

1) Mr Ho had a total of 102 pink and white roses in the ratio of 12:5.

After he has given away twice as many pink roses as white roses, the number of pink and white roses left was in the ratio 5:2.

How many pink roses did he give away?

2) Last year, the ratio of boys to girls in a school’s computer club was 4 : 7 . This year, 71 new members joined the club.

As a result, the ratio of boys to girls in the club becomes 4 : 3 . There are 72 boys in the club this year. How many of the new members are girls?

Q: 1692365

Subject: Math

Level: P6

Tags: Ratios

Source: ???

^^^

Please help:

1) Mr Ho had a total of 102 pink and white roses in the ratio of 12:5.

After he has given away twice as many pink roses as white roses, the number of pink and white roses left was in the ratio 5:2.

How many pink roses did he give away?

2) Last year, the ratio of boys to girls in a school’s computer club was 4 : 7 . This year, 71 new members joined the club.

As a result, the ratio of boys to girls in the club becomes 4 : 3 . There are 72 boys in the club this year. How many of the new members are girls?