Answer:
Option A
Explanation:
concept involved
it is a simple application of independent event, us to solve a certain problem or any type of competition each event is independent of order.
Formula used
$P(A\cap B)=P(A).P(B)$ When A and B are independent events
probability that the problem is solved correctly by atleast one of them =1-(problem is not solved by all)
$\therefore$ P (problem is solved )=1-P
(Problem is solved)
$=1-P(\overline{A)}.P(\overline{B)}.P(\overline{C)}.P(\overline{D)}$
= $1-\left(\frac{1}{2}.\frac{1}{4}.\frac{3}{4}.\frac{7}{8}\right)$
=$1-\frac{21}{256}=\frac{235}{256}$
