BITSAT2014MathematicsProbabilityActual
A coin is tossed 7 times. Each time a man calls head. Find the probability that he wins the toss on more occasions.
Options
- A2 3
- B1 2
- C3 4
- D1 3
Correct answer
B. 1 2
Step-by-step solution
The man has to win at least 4 times. array r Reqd. probability = array r 7 C ₄ ( 1 2 )⁴ ( 1 2 )³+ ⁷ C ₅ ( 1 2 )⁵ ( 1 2 )² + ⁷ C ₆ ( 1 2 )⁶ 1 2 + ⁷ C ₇ ( 1 2 )⁷ = ( ⁷ C ₄+ ⁷ C ₅+ ⁷ C ₆+ ⁷ C ₇ ) 1 2⁷ = 64 2⁷ = 1 2 array array