Question

a coin is tossed 2 times find the probability of getting atmost one head

Answer 1

For two (random) coin tosses you have four possible combinations:

The first toss gives Head, the second toss gives HeadThe first toss gives Head, the second toss gives TailsThe first toss gives Tails, the second toss gives HeadsThe first toss gives Tails, the second toss gives Tails

I have highlighted the three cases out of four where at least one Head is obtained.

The probability is therefore 75%, or .75, or ¾

Answer 2

the answer is     =     3/4
bez. HH TH HT