Answer to Question #47190 in Statistics and Probability for irebami

Question

The probabilities of a boy passing English and Mathematics tests are x and y respectively. Find the probability of the boy failing both tests.

1-(x-y)+xy
1-(x+y)-xy
1-(x+y)+xy
1-(x-Y)-xy

Answer 1

The probability of the boy failing both tests is (1-x)(1-y)=1-y-x+xy=1-(x+y)+xy.