If U = {x : x is an integer and 1 \(\leq\) x \(\leq\) 20}
E1 = {x : x is a multiple of 3}
E2 = {x : x is a multiple of 4}
and an integer is picked at random from U, find the probability that it is not in E2
-
3/4
- 3/10
- 1/4
- 1/20
The correct answer is: A
Explanation
U = {1, 2, 3, 4, 5,..., 20}
E1 = {3, 6, 9, 12, 15, 18}
E2 = {4, 8, 12, 16, 20}
P(E\(_2\)) = \(\frac{5}{20}\)
P(not E\(_2\)) = 1 - (\(\frac{5}{20}\)) = \(\frac{15}{20} = \frac{3}{4}\)
There is an explanation video available .