Question

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: option 1 : 4/19 option 2 : 7/19 option 3 : 12/19 option 4 : 21/95

Answer 1

Answer:

7 / 19

Step-by-step explanation:

P (none is defective)

= n (E) = 16C220C2=

[(16×15) / (2×1)] × [(2×1) / (20×19)]

=12 / 19

P (at least 1 is defective)

=(1−12 / 19)

=7 / 19