Answer:

The probability of getting a defective bulb is 1/5 ( in percentage form =  20% )

Step-by-step explanation:

Given:

A lot of 20 bulbs contain four defective bulbs.

One bulb is drawn from the lot

To Find:

Probability of getting defective bulb

Calculation:

Total Number Bulbs (Total Number of Sample Space) = 20

Total Number of defective bulbs (Total Number of favorable outcomes) = 4

Probability of the getting defective bulb = 4/20 = 1/5 (or, 20%)

Hence, The probability of getting a defective bulb is 1/5 or 20% (ans.)