BITSAT2019MathematicsProbabilityActual
A die is thrown 7 times. What is the probability that an even number turns up at least 4 times?
Options
- A1 2
- B31 64
- C51 128
- D35 128
Correct answer
A. 1 2
Step-by-step solution
For atleast 4 times an even number, probability is = C 4 7 1 2 4 1 2 3 + C 5 4 1 2 5 1 2 2 + C 6 7 1 2 6 1 2 1 + C 7 7 1 2 7 = 1 2