A group of pupils sat for two tests, test A and test B. The number of pupils who failed test A was 1/7 of those who passed test A. Given that there were 20 pupils who failed test A,

(a) How may pupils passed test A?

(b) The number of pupils who failed test B was 1/4 of those who failed test A. What fraction of the pupils passed test B?

Solution

(a)

1 unit ----- 20

7 units ----- 20 x 7 = 140

Answer: 140 pupils

(b)

Failed Test A ----- 20

Failed Test B ----- 1/4 x 20 = 5

(Total number of pupils)

8 units ----- 8 x 20 = 160

Fraction of pupils who failed Test B

5/160 = 1/32

Fraction of pupils who passed Test B

1 – 1/32 = 31/32

Answer: 31/32

This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

## Thursday, September 17, 2009

### Raffles Girls Pri Sch 2007 PSLE Math Prelim Q44

Labels:
Fractions,
Mathematics

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## 1 comment:

How many pupils are there in the group?

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