Question:
If the radii of the circular ends of a bucket of height 40 cm are of lengths 35 cm and 14 cm, then the volume of the bucket in cubic centimeters, is
(a) 60060
(b) 80080
(c) 70040
(d) 80160
Solution:
Height of the bucket = 40 cm
Radius of the upper part of bucket = 35 cm
R1 = 35 cm and
R2 = 14 cm
The volume of the bucket
$=\frac{1}{3} \pi h\left(r_{1}^{2}+r_{2}^{2}+r_{2}^{3}\right)$
$=\frac{1}{3} \times \frac{22}{7} \times 40\left[(35)^{2}+(14)^{2}+(35 \times 14)\right]$
$=\frac{1}{3} \times \frac{22}{7} \times 40[1225+196+490]$
$=\frac{1}{3} \times \frac{22}{7} \times 40 \times 1911$
$=\frac{1681680}{21}$
$=80080 \mathrm{~cm}^{3}$
Hence, the correct answer is choice (b).