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A six-faced fair dice is rolled five times. The probability (in%) of obtaining "ONE" at least four times is
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- 33.3
- 3.33
- 0.33
- 0.0033
Correct Option: C
A dice is rolled 5 times
n = 5
P = (Probability of getting 1) = 1/6
| 0% q = 1 - p = 1 - | = | ||
| 6 | 6 |
Probability of getting 1 at least 4 times is
P(x ≥ 4) = P(x = 4) + P(x = 5)
= nC4p4qn-4 + nC5p5qn-5[∵ nCrpxqn-x
= 5C4p4q0
| = 5 × |  |  | 4 | | | 1 | + 1 × | | | 5 | | | 0 | ||||||
| 6 | 6 | 6 | 6 |
| = | + | = | = 0.0033 | |||
| (6)5 | (6)5 | (6)5 |
Required probability = 0.33%
