Question

Two unbiased coins are tossed. the probability of obtaining at least one head is:



a. 1/4



b.2/4



c.3/4



d.0

Answer 1

When 1 coin is tossed total outcomes will be 2

when 2 coins are tossed total outcomes will be 4

when n coins are tossed total outcomes will be 2^n

Hence here total outcomes are 4 and these outcomes will be {H,H},{H.T},{T,T},{T,H}

probability for for atleast one head i.e., it may be 1 or 2  heads is 3/4