Question

The probability that bulbs selected randomly from the lot has life less than 900 h, is
A. `11/40`
B. `5/16`
C. `7/16`
D. `9/16`

Answer 1

Correct Answer - D
Total number of bulbs in a lot, n(S)=80
Number of bulbs whose life time is less than 900h, n(E ) =10 + 12 + 23=45
`therefore` Probability that bulbs has life time less than 900 h`=(n(E ))/(n(S))=45/80=9/16`
Hence, the probability that bulb has life time less than 900 is `9/16`.