A bag contains 5 red, 3 blue and 2 green marbles. One marble is drawn at random. Find the probability that the marble is not blue.

Step-by-step solution

1. Let the event $E$ be drawing a blue marble.
2. $P(E)=\frac{\text{number of blue marbles}}{\text{total marbles}}=\frac{3}{10}$.
3. The probability of not $E$ is the complement: $P(E^c)=1-P(E)=1-\frac{3}{10}=\frac{7}{10}$.
4. Thus the required probability is $\frac{7}{10}$.

Concept tested: Complement rule

Published 4 October 2026 · How this solution was prepared and checked