JAMB 1991 · UME · Q46

Find the volume of the figure: a cone of height $x$ on top of a cylinder of height $y$ , both of radius $a$ .

Worked solution (try it first)

Cone: $\frac13\pi a^2x$ .
Cylinder: $\pi a^2y$ .
Add them and take out the common factor $\pi a^2$ : $\pi a^2\left(\frac x3 + y\right)$ , option D.