"A box contains 20 electric bulbs, out of which 4 are defective. Two balls are chosen at
Channel: Doubtnut
Date: 2020-04-05

"A box contains 20
 electric bulbs, out of which 4 are defective. Two balls are chosen at random
 from this box. The probability that at least one of them is defective, is
`4/(19)`
(b) `7/(19)`
(c) `(12)/(19)`
(d) `(21)/(95)`
(e) None of these"