Aptitude Day 132

Problems on Probability:

1. 3 unbiased coins are tossed. What’s the probability of getting at most 2 tails?

Solution:

                S = {TTT, TTH, THT, HTT, HHH, HHT, HTH, THH}

                E = {TTH, THT, HTT, HHH, HHT, HTH, THH }

               P(E) = n(E)/ n(S)

                       = 7/8.

2. In a single throw of a die, what’s the probability of getting a number greater than 3?

Solution:

                  S = {1, 2, 3, 4, 5, 6}

                  E = {4, 5, 6}

                 P(E) = n(E)/ n(S)

                        = 3/6

                        = 1/2.