There are 10 rolls of film in a box and 3 are defective. Two rolls are selected without replacement. What is the probability of selecting a defective roll followed by another defective roll?
A) ½ or 0.50
B) ¼ 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 the first defective roll is 3/10. After removing one defective roll, there are 2 defective rolls left out of 9 total rolls. The probability of selecting a second defective roll is 2/9. Multiply these probabilities: (3/10) * (2/9) = 1/15.

There Are 10 Rolls of Film in a Box and 3