How do i find the volume of a rectangular pyramid?

Fractions can be added and subtracted only if they're fractions. a. like b. proper c. improper d. unlike

Asocial networking site currently has 400,000 active members, and that figure is predicted to increase by 32% each year. the following expression represents the number of active members on the site after t years.

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?