A coin is tossed 7 times. The probability of getting at least 4 heads is:
Answer & explanation
Correct answer: option 4
Coin tossed 7 times
P(atleast 4 heads)
= P(4 heads) + P(5 heads) + P(6 heads) + P(7 heads)
$=\frac{{^7C}_4+{^7C}_5+{^7C}_6+{^7C}_7}{2^7}=\frac{35+21+7+1}{128}=\frac{64}{128}$
$=\frac{1}{2}$