7.20 Let x denote the lifetime (in thousands of hours) of a certain type of fan used in diesel engines. The density
curve of x is as pictured:
0
25
50
Shade the area under the curve corresponding to each
of the following probabilities (draw a new curve for
each part):
a. P(10 b. P(10 Sxs 25)
c. P(x < 30)
d. The probability that the lifetime is at least 25.000 hr
e. The probability that the lifetime exceeds 25.000 hr