Time and Distance Practice Test 4 with solutions

Distance covered by ball just before it hits the ground for the first time = 120 feet
In the second round, the distance covered by the ball = $\left(120\times \frac{4}{5}\right)\times 2$
In the third round, the distance covered by the ball = $120\times {\left(\frac{4}{5}\right)}^2\times 2$
In the fourth round, the distance covered by the ball = $120\times {\left(\frac{4}{5}\right)}^2\times 2$
Hence, the required distance :
=
= $120+2\times 120\left[\frac{4}{5}+\frac{16}{25}+\frac{64}{125}+...\right]$
= 120 + $240\left[\frac{\frac{4}{5}}{1-\frac{4}{5}}\right]$
= 120 + $240\left[\frac{4}{5}\times \frac{5}{1}\right]$
= 120 + 960 = 1,080 metres