Question

Description: Twenty caravans are travelling across the desert one day apart. The

first caravan reached the oasis and the camels drank half of the water in the pool.

On the second day, the second caravan reached the oasis and the camels drank

one-third of the water that was left. On the third day, the camels in the third

caravan drank one-quarter of the water that was left. On the first day the pool

contained 1050m3 of water. How much water was left after the 20th caravan

passed through.

Hint: Observe the pattern and calculate.​

Answer 1

The first caravan left half of the water. The second caravan left

$\begin{gathered} \frac{2}{3} \times \frac{1}{2} = \frac{1}{3} \\ \frac{3}{4} \times \frac{1}{3} = \frac{1}{4} \end{gathered}$

of the water. Continuing the pattern, the 20th caravan leaves

$\frac{1}{21} \: or \: 50 m {}^{3} \: of \: water.$