Question
From a lot containing 10 defective and 90 non-defective bulbs, 8 bulbs are selected one by one with replacement. Then the probability of getting at least 7 defective bulbs is
JEE Main
Mathematics
Probability
2026
JEE Main 2026 (24 January Shift 1)
JEE Main Mathematics Question (2026) — Solution
Options
- A. 67 10^ 8
- B. 7 10^ 7
- C. 81 10^ 8
- D. 73 10^ 8
Answer
D. 73 10^ 8
Step-by-step solution
Binomial distribution with n=8, p= 1 10 , q= 9 10 . P(X 7) = P(X=7) + P(X=8) P(X=7) = 8 7 ( 1 10 )^7 ( 9 10 ) = 72 10^8 P(X=8) = ( 1 10 )^8 = 1 10^8 P(X 7) = 73 10^8
Related: Mathematics — Probability · All PYQ Banks