Question

When two pumps are activated, an empty pool takes 12 hours to fill. One of the pumps works 3 times faster than the other. How many hours would it take to fill the pool if only the faster pump were used

Answer 1

Let t be the time for only the faster pump tp fill the empty pool. Then the time for only the slower pump to fill the empty pool is 3t. Now we can write the equation:
$\frac{1}{t}+\frac{1}{3t}=\frac{1}{12}$
Solving this equation for t gives:
t = 16 hours