Question

When three coins are tossed simultaneously find the probability of atmost two head

Answer 1

First, we make sample space for getting head or tail for 3 coins, tossed simultaneously…

Order is 1st coin, 2nd coin, 3rd coin, H for head & T for tail

HHT ……..●

HTH ……..●

HTT…….. ●

HHH

THT……….●

TTH………..●

TTT………..●

THH …….●

Here, we can see that Total no of outcomes = 8

And no of outcomes favourable to event getting at most 2 heads.= means all should not be heads ( meansHHH is exempted), means starting from no heads, gradually you can go up to 2 at the most)

So outcomes favourable to the event (getting 2 heads at most) = 8–1 = 7

Probability ( E) = (favourable outcomes)/ (total outcomes) = 7/8

ANS: 7/8