Question

A can solve $90\%$ of the problems given in a book and B can solve $70\%$. What is the probability that at least one of them will solve a problem selected at random from the book?

Answer 1

Probability that no one can solve the question :

$=(1-\frac{90}{100})\times (1-\frac{70}{100})$

$=0.1\times 0.3$

$=0.03$

Probability that one of them solves it $=1-0.03$

$=0.97$

$=\frac{97}{100}$

Hence, the answer is $\frac{97}{100}.$