A hose, working alone, is capable of filling up an empty pool in 6 hours◉ Rate of First Hose = X
◉ Let work done = 1
Using Rate * Time = Work Done
X * 6 = 1
=> X = \(\frac{1}{6}\)
A second hose, working alone, is capable of filling up the empty pool in 4 hours. ◉ Rate of Second Hose = Y
◉ Work done = 1
Using Rate * Time = Work Done
Y * 4 = 1
=> Y = \(\frac{1}{4}\)
How long would it take for both hoses together to fill two-thirds of the pool? ◉ Combined Rate = X + Y = \(\frac{1}{6}\) + \(\frac{1}{4}\) = \(\frac{10}{24}\) = \(\frac{5}{12}\)
◉ Work done = \(\frac{2}{3}\)
Using Rate * Time = Work Done
\(\frac{5}{12}\) * Time = \(\frac{2}{3}\)
=> Time = \(\frac{2 * 12}{3 * 5}\) = \(\frac{8}{5}\)
=> Time = 1 + \(\frac{3}{5}\) hours = 1 hour + \(\frac{3 * 60}{5}\) mins = 1 hour 36 mins
So,
Answer will be \(\frac{8}{5}\) or 1 hour 36 minsHope it helps!
Watch following video to
MASTER Work Rate Problems