When four unbiased coins are tossed, then what is the probability of getting…

Step-by-Step Solution

When tossing four unbiased coins, the total number of possible outcomes is 2^4 = 16. To find the probability of getting "at most two tails," we need to sum the number of outcomes that result in zero, one, or two tails.

1. Calculate the number of outcomes for each case (using combinations):

   • Zero tails (all heads): 4C0 = 1 outcome (HHHH)

   • One tail: 4C1 = 4 outcomes (THHH, HTHH, HHTH, HHHT)

   • Two tails: 4C2 = (4 * 3) / (2 * 1) = 6 outcomes (TTHH, THTH, THHT, HTTH, HTHT, HHTT)

2. Sum the favorable outcomes:

   • Total favorable outcomes = 1 + 4 + 6 = 11.

3. Calculate the probability:

   • Probability = (Total Favorable Outcomes) / (Total Possible Outcomes)

   • Probability = 11 / 16.