Question

The height that a ball bounces varies directly with the height from which it is dropped. A certain ball bounces 30 cm when dropped from a height of 50 cm. How high will the ball bounce if dropped from a height of 120 cm?

Answer 1

The ball will bounce 72 cm high if dropped from a height of 120 cm

Solution:

Given, The height that a ball bounces varies directly with the height from which it is dropped.  

A certain ball bounces 30 cm when dropped from a height of 50 cm.  

We have to find how high will the ball bounce if dropped from a height of 120 cm?

Now, according to given information,

When dropped from 50 cm ⇒ bounces 30 cm

Then, when dropped from 120 cm ⇒ bounces "n"  cm

Now by Chris cross method, we get,

$\begin{array}{l}{n \times 50=30 \times 120} \\\\ {\rightarrow n=\frac{30 \times 120}{50}} \\\\ {\rightarrow n=\frac{3600}{50}} \\\\ {\rightarrow n=72}\end{array}$

Hence, the ball bounces 72 cm high.