Using the formula in the hint replace P(B) with 25%
P(B^c) = 1 - 0.25 = 0.75 = 75%
Given P(B)= 25% => 25/100
Hence, P(B^C) = 1 - 25/100 => (100 - 25)/100 => 75/100
So, P(B^C) = 75%
Hope it helps
