If a random variable waiting time in minutes for bus and probability density function of x is given by
`f(x)={{:(1/5","0lexle5),(0",""otherwise"):}`
Then probability of waiting time not more than 4 minutes is equal to

Options

A. 0.3
B. 0.8
C. 0.2
D. 0.5

Answer

B

Explanation

Given, `f(x)={{:(,(1)/(5), 0 le x le 4),(,0,"otherwise"):}`
`therefore P(0 le x le 4)=underset(0)overset(4)f(x)dx=underset(0)overset(1) dx=(1)/(5)[x]_(0)^(4)`
`=(1)/(5)(4-0)=(4)/(5)=0.8`