Answer:
The probability that exactly two of the selected bulbs are rated 23-watt is:
= 19%
Step-by-step explanation:
Number of fluorescent light bulbs in the box = 21
7/21 = 13-watt rated light bulbs
8/21 = 18-watt rated light bulbs
6/21 = 23-watt rated light bulbs
The probability of selected a 23-watt rated light bulb = 6/21 = 28.57%
Size of random selection of bulbs = 3
The probability that 2 out of these 3 bulbs are 23-watt rated light bulbs is:
= 6/21 * 2/3 = 19%
b) The probability of selecting 2 of the 3 bulbs from exactly the 23-watt rated bulbs is the probability of the 23-watt rated bulbs being selected given the chance of selecting 2/3.
