Question

Odds against Praveen solving a problem is 1 out of 5. If the probability of Praveen solving the problem is p, then 120p = ___

Answer 1

Odds against an event is the ratio of number of unfavorable outcomes and number of favorable outcomes. We know that total number of outcomes will be equal to favorable outcomes (n) + unfavorable outcomes(m).
Odds against Praveen solving the problem $=\frac{1}{5}=\frac{m}{n}$
$\Rightarrow$ n = 5m
Probability of Praveen solving the question $=\frac{n}{m+n}$
$=\frac{5m}{m+5m}$ $=\frac{5}{6}$
$\Rightarrow 120p=120\times \frac{5}{6}$
= 100