anik89 wrote:
a groups of four pumps filling a tank. each of the 3 smaller pumps work at 2/3 the rste of lsrgest pump. if all 4 pumps work at the same time, they should fill the tank in what fraction of the time that it would have taken the largest pump if it operated alone?
ans - 1/3
Assume that the rate of pumping of largest pump be 60 lt/hour and let tank be 60 liters.
So largest pump working alone will fill the tank in 1 hr.
Now the smaller pumps pump at \(\frac{2}{3}* 60\) lt/hr = 40 lt/hr.
So working together we have pumping rate = \((60 + 3* 40)\) lt/hr = 180 lt/hr
So the fraction of time = \(\frac{60}{180}\) = \(\frac{1}{3}\)