Multiple choice

A box contains 5 brown and 7 black pebbles. What is the probability of drawing a brown pebble if the first pebble drawn is black? The balls drawn are not replaced in the box.

  1. 5/11

  2. 8/11

  3. 4/18

  4. 14/11
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Initially 5 brown, 7 black (total 12). If one black is drawn, 5 brown and 6 black remain (total 11). Probability of drawing a brown pebble is 5/11.

AI explanation

Because the first drawn black pebble is not replaced, the box now contains 5 brown pebbles and 6 black pebbles. The total number of remaining pebbles is 11. The probability of drawing a brown pebble from this reduced set is 5 out of 11, which is 5/11.

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