49. The article “Monte Carlo Simulation—Tool for Better Understanding of LRFD” (J. Struct. Engrg., 1993: 1586 –1599) suggests that yield strength (ksi)

for A36 grade steel is normally distributed with m

43 and s  4.5.

a. What is the probability that yield strength is at most 40? Greater than 60?

b. What yield strength value separates the strongest 75% from the others?