Question

A student answers

Answer 1

So, we have the percentage she gets which is, 90% and the number of questions she answers correctly, which is 27

To find the number of questions in the exam, make an equation
(90% = $\frac{90}{100}$ = 0.9)
$\frac{90}{100}$ = $\frac{27}{x}$
cross multiply and equate them
90x = 27 x 100
90x = 2700
divide by 90 on either sides to isolate x in order to find the answer
$\frac{90x}{90} = \frac{2700}{90}$
90 and 90 cancels out
x = 30
So your final answer will be, there were 30 questions in the exam paper.