A box of 11 transistors has 7 defective ones. If 2 transistors are drawn from the box together, what is the probability that both transistors are defective? Round your answer to two decimal places.

Question

A box of 11 transistors has 7 defective ones. If 2 transistors are drawn from the box together, what is the probability that both transistors are defective? Round your answer to two decimal places. ​

Quizplus · Accepted Answer

The probability of drawing a defective transistor on the first draw is 7/11. 
After one defective transistor is drawn, there are 6 defective transistors left in a box of 10 transistors.
Therefore, the probability of drawing another defective transistor on the second draw is 6/10.
The probability of both events happening together is:
(7/11) x (6/10) = 42/110 = 0.38 (rounded to two decimal places).
Therefore, the correct choice is B.

A Box of 11 Transistors Has 7 Defective Ones