Quote:
Pump A and B together put water in the empty tank of which volume is x. Let \(R_A\) = rate of A and \(R_B\) = rate of BWe know that Work = rate*timeWe can say: (\(R_A\) + \(R_B\))*t = x We need to find time t.Quote:
If machine A put 1-gallon of water more than machine B for every minute, how many hours A and B work together? (\(R_A\))*1 = g +1
(\(R_B\))*1 = g
We can subtract the above equations to get: (\(R_A\)) - (\(R_B\)) = 1
Now let's look at the statements:
(1) Machine A put 100 gallon more than machine BFor the same time 't' working alone, Machine A puts 100 gallon more than machine B. Let's write it as:\(R_A\)*t = G + 100\(R_B\)*t = GWe can subtract the above equations to get: (\(R_A\) - \(R_B\))*t = 100 => t = (100)/(\(R_A\) - \(R_B\))We can substitute \(R_A\) - \(R_B\) = 1 to get t = 100 minutes. Therefore, Statement (1) is sufficient. Let's check statement (2) now.(2) Two machines put total 800 gallon of waterThis gives us the value of x = 800.(\(R_A\) + \(R_B\))*t = x => (\(R_A\) + \(R_B\))*t = 800We still don't know the sum of the rates of A and B so we can't calculate the time. Therefore, Statement (2) is not sufficient. Hence answer is (A).