4(.75) + 3
3 + 3
6
-------------------
6(.50) - 2
3 - 2
1
P = 2 (l + w)
P = 2(6 + 1)
P = 2 x 7
P = 14
here (I need 20 characters in order to send this so don't mind this text)
I suppose the density is supposed to be

(since
diverges as
, and 0 is conveniently left out of the domain)
For this to be a proper density function, it must be positive (it is) and its integral over the support
must evaluate to 1. We have

which means
.
The distribution function is obtained by integrating the density:

The probability that the component exceeds 2 years in its lifetime is

Angle b is 65
In order for a shape to be a triangle, all sides have to add up to 180 degrees. Since 65 + 50 = 115 and 180 - 115 = 65,
65 is the answer for angle b