sandy wrote:
A standard machine fills paint cans at a rate of 1 gallon every 4 minutes. A deluxe machine fills gallons of paint at twice the rate of a standard machine. How many hours will it take a standard machine and a deluxe machine, working together, to fill 135 gallons of paint?
(A) 1
(B) 1.5
(C) 2
(D) 2.5
(E) 3
Here ,
The standard machine rate = \(\frac{1}{4} *60 minutes = 15 gallons/ hr\)
The deluxe machine rate = \(2 * standard machine rate = 30 gallons/hr\)
Therefore working together they fills = \(15 + 30 = 45 gallons/hr\)
Now to fill 135 gallons of paint
We know \(Work = Rate * Time\)
or \(135 = 45 * time\)
or \(time = \frac{135}{45} = 3 hr\)
_________________
If you found this post useful, please let me know by pressing the Kudos ButtonRules for PostingGot 20 Kudos? You can get Free GRE Prep Club TestsGRE Prep Club Members of the Month:TOP 10 members of the month with highest kudos receive access to 3 months
GRE Prep Club tests