Question

There are 520 bridges on the freight rail network in the province of Ostenborg. Of these, 200 are classified as “old” rail bridges (i.e., 50 years or more in age). Past records indicate that 50% of all rail bridges in the state exhibit visible signs of structural distress. Of the bridges 70% are old or exhibit structural distress.

Find the probability that a randomly selected rail bridge will exhibit structural distress given that it is old.

Answer 1

The probability that a selected randomly rail bridge will exhibit structural distress given that it is old

= (200/520) * 0.5 * 0.7 * 100

= 0.1346154 * 100

= 13.46154 %