Question

A box contains 50 batteries, of which 10 are dead and 5 are weak. Suppose you select batteries at random from the box and set them aside for recycling if they are dead or weak. If the first battery you select is dead and the second one is weak, what is the probability that the next battery you select will be weak?

Answer 1

Probability of selecting 1 dead, 1 weak, then 1 weak = (1/588).

Given: 50 total batteries, of which 10 are dead and 5 are weak. This is represented by: 10/50 (simplifies to 1/5) and 5/50 (simplifies to 1/10).
If the batteries are being set aside, it likely means no replacement. For every battery taken out of the box, the box holds one less battery.

Probability of selecting 1 dead, 1 weak, 1 weak is written as: (10/50)*(5/49)*(4/48) = 1/588.