when two coins are tossed simultaneously, under P(at most one head), what all possible outcomes shall come under it and why?......i have seen the video but i am still confused

When two coins are tossed simultaneously then the possible outcomes obtained are HH, HT, TH, and TT}. Here H denoted head and T denotes tail.

Therefore, a total of 4 outcomes obtained on tossing two coins simultaneously.

 

Consider the event of obtaining at most one head. At most one head is obtained means either no head is obtained or one head is obtained.

 

The outcome(s) favourable to no head obtained is {TT}

The outcome(s) favourable to one head obtained is {HT, TH}

 

Therefore, the event of obtaining at most one head has 3 favourable outcomes. These are TT, HT and TH.

 

Therefore, the probability of obtaining at most one head = 3/4.