Question

Sonu was making sand pyramids at the beach. He designed his pyramids with a base edge of 10 cm and height 33 cm. He would go collect wet sand with his small cylindrical bucket of radius 5 cm and 7 cm height. How many times does he need to collect the wet sand in order to construct his sand pyramid?

• A. Volume of cone = volume of sphere
• B. Surface area of cone = Surface area of sphere
• C. Radius of cone = Radius of Radius of sphere
• D. Height of cone = Height of cylinder

Answer 1

The correct option is B

Surface area of cone = Surface area of sphere

Given dimensions of the pyramid, $a=10cm,h=33cm$

Volume of sand needed to make the pyramid $=\frac{1}{3}{a}^{2}h=\frac{1}{3}.{10}^2.33=1100c{m}^3$

Given dimensions of the bucket, $r=5cm,h=7cm$

Volume of sand carried by the bucket $=\pi r^{2}h=\frac{22}{7}.5^2.7=550c{m}^3$

Number of trips needed to get volume of sand pyramid, $=\frac{\text{Volume of pyramid}}{\text{Volume of bucket}}=\frac{1100}{550}=2$

Sonu needs to make 2 trips to collect wet sand to make his pyramid.