Question

Eight coins are tossed simultaneously. Then the probability of obtaining at least 6 heads is

Answer 1

We already know that there are exactly 2possible outcomes for each and every toss of coins, namely {H & T}.

Therefore, total no. of possible outcomes will be same as no. of binary strings of length 8=28=256

This is our sample space.

Now, we need to count no. of favorable events,

i.e.

no. of outcomes in which there are 6 heads, or 7 heads or 8 heads.

This will be same as

no. of ways to select 6 coins out of 8 + no. of ways to select 7 coins out of 8 + no. of ways to select 8 coins out of 8

=8C6+8C7+8C8

=28+8+1

=37

Therefore, probability of getting at least 6 heads

=(37256)