Question

A batch consists of 12 defective coils and 88 good ones. Find the probability of getting two good coils when two coils are randomly selected if the first selection is replaced before the second is made. 0.7744 0.7733 0.0144 0.176

Answer 1

The probability of getting two good coils when two coils are randomly selected if the first selection is replaced before the second is made is 0.7744

Solution:

Total number of coils = number of good coils + defective coils = 88 + 12 = 100

p(getting two good coils for two selection) = p( getting 2 good coils for first selection )
`*` p(getting 2 good coils for second selection)

p(first selection) = p(second selection) =
`\frac{\text { number of good coils }}{\text { total number of coils }}`

Hence, p(getting 2 good coil for two selection) =
`(88)/(100) * (88)/(100) =\bold{0.7744}`