A box contains 20 electric bulbs, out of which 4 are defective. Two bulbs are chosen at random from this box. The probability that at least one of these is defective, is:
A. 4/19
B. 7/19
C. 12/19
D. 21/95
Answer:B
A box contains 20 electric bulbs, out of which 4 are defective. Two bulbs are chosen at random from this box. The probability that at least one of these is defective, is:
A. 4/19 B. 7/19 C. 12/19 D. 21/95
Explanation: P( None is defective)