Out of 70 schools, 42 of them can be attended by boys and 35 can be attended by girls. If a pupil is selected at random from these schools, find the probability that he/ she is from a mixed school.
-
A.
(frac{1}{11}) -
B.
(frac{1}{10}) -
C.
(frac{1}{6}) -
D.
(frac{1}{5})
Correct Answer: Option B
Explanation
Let the number of mixed schools be S
The number of boys only = 42 – S
The number of girls only = 35 – S
(42 – S) + S + (35 – S) = 77 – S = 70
(implies) S = 7
(Probability = frac{7}{70} = frac{1}{10})