There are 10 AAA batteries in a box and 3 are defective. Two batteries are selected without replacement. What is the probability of selecting a defective battery followed by another defective battery?
A)1/2 or 0.50
B)1/4 or 0.25
C)1/120 or about 0.0083
D)1/15 or about 0.07

Question

Quizplus · Accepted Answer

The probability of selecting a defective battery first is 3/10. After removing one defective battery, there are now 9 batteries left, with 2 being defective. The probability of then selecting another defective battery is 2/9. Multiplying these probabilities gives (3/10) * (2/9) = 6/90 = 1/15.

There Are 10 AAA Batteries in a Box and 3