Question

A thirsty crow wants to raise the level of water in a cylindrical container so that it can reach the water with its beak.

The container has a diameter of 2 inches and a height of 9 inches
The water level is currently at 6 inches
The crow can reach the water if it is 1 inch from the top of the container.
The crow puts pebbles in the water to raise the water level
If the pebbles have a diameter of 1/2 inches , what is the fewest number of pebbles the crow needs to drop in the water to reach the water?

Answer 1

Explanation:

calculate volume(V1) of each pebble whose diameter is 1/2 inches.

calculate the volume of increased level portion(V2) height=9-(6+1)=2inches and diameter 2inches.

Then,

Use formula,

N=V2/V1