Chapter 13.5, Problem 55E

(a)

To determine

To calculate: The definite integral ${\displaystyle \underset{20}{\overset{30}{\int }}f(x)dx}$.

(b)

To determine

To calculate: The definite integral ${\displaystyle \underset{0}{\overset{90}{\int }}f(x)dx}$.

(c)

To determine

To calculate: The number of millennials who were between $\text{10 and 30 years}$ of age.