Question

two coins are tossed 100 times and the outcomes are 2 heads- 15，1 head- 52,0 head- 33. find the probability of at most 1 head.

Answer 1

Two coins are tossed 100 times and the outcomes are 2heads-15, 1 head-52 and 0 head -33. 
At most one head means either 1 head or less than 1 head that is 0. Now among those 52 one head outcomes there are 15 two heads outcomes.
∴, the probability of at most one head is
=[(52-15)+33]/100
=(37+33)/100
=70/100
=7/10