A bag contains 7 white balls and 3 black balls. One ball is drawn at random. Find the probability that the ball drawn is black.

Step-by-step solution

1. Count the total number of balls: $7+3=10$.
2. Count the number of favourable outcomes (black balls): $3$.
3. Use the formula $P=\frac{\text{favourable}}{\text{total}}$.
4. Substitute the values: $P=\frac{3}{10}$.

Concept tested: Simple probability

Published 22 August 2026 · How this solution was prepared and checked

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