Question

A school sent up 80 candidates for an examination and school result was 70% pass How many candidates should be detained so that the result becomes 80% pass?

• A. 16
• B. 12
• C. 10
• D. 8

Answer 1

The correct option is C 10

Given the result an examination 80 candidates is 70%

Then pass candidates=$\frac{70}{100}\times 80=56$

Let x candidates should be detained so result become 80 %

$\therefore \frac{80}{100}\times (80-x)=56$

$\Rightarrow 640-8x=560$

$\Rightarrow 8x=80$

$\Rightarrow x=10$