In the first 2 hours after Meadow's self-service laundry

[BTGmoderatorDC]

In the first 2 hours after Meadow's self-service laundry opens, m large washing machines and n small washing machines are in continual use. Including the time for filling and emptying the washing machines, each load of laundry takes 30 minutes in a large washing machine and 20 minutes in a small washing machine. What is the total number of loads of laundry done at Meadow's self-service laundry during this 2-hour period?

(1) n = 3m
(2) 2m + 3n = 55


OA B

Source: Official Guide

[Jay@ManhattanReview]

In the first 2 hours after Meadow's self-service laundry opens, m large washing machines and n small washing machines are in continual use. Including the time for filling and emptying the washing machines, each load of laundry takes 30 minutes in a large washing machine and 20 minutes in a small washing machine. What is the total number of loads of laundry done at Meadow's self-service laundry during this 2-hour period?

(1) n = 3m
(2) 2m + 3n = 55

OA B

Source: Official Guide

Given that each load of laundry takes 30 minutes in a large washing machine, in 2 hours, there will be 4 loads per machine. Since there are m large machines, there would be 4m load; similarly, given that each load of laundry takes 20 minutes in a small washing machine, in 2 hours, there will be 6 loads per machine. Since there are n small machines, there would be 6n load.

Thus, total number of load = 4m + 6n.

So, we have to get the value of 4m + 6n.

Let's take each statement one by one.

(1) n = 3m

total number of load = 4m + 6n = total load = 4m + 6*3m = 22m. Can't get the value. Insufficient.

(2) 2m + 3n = 55

=> total number of load = 4m + 6n = 2(2m + 3n) = 2*55 = 110. Sufficient.

The correct answer: B

Hope this helps!

-Jay
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[deloitte247]

Large machine = m
Small machine = n
Given that load of laundry for 'm' takes 30 minutes, and load of laundry for 'n' takes 20 minutes.
2 hours = 2 * 60 minutes = 120 minutes
For m in 2 hours = 120/30 = 4
For n in 2 hours = 120/20 = 6
m loads in 2 hours = 4m
n loads in 2 hours = 6n
What is the total number of loads of laundry done at Meadow's self-service laundry during this 2-hour period?
i.e 4m + 6n = ??
Statement 1: n = 3m
4m + 6 (3m) = x
4m + 18m = x
x = 22m
However, the value of m is unknown, hence, statement 1 is NOT SUFFICIENT.

Statement 2: 2m + 3n = 55
Multiply through by 2
4m + 6n = 110
The total loads in 2 hours = 110 laundries. Thus, statement 2 alone is SUFFICIENT.

The correct answer, therefore, is option B.