Blog

# The Quest for 700: Weekly GMAT Challenge (Answer)

Yesterday Manhattan GMAT posted a GMAT question on our blog. Today, they have followed up with the answer:

Let t stand for the desired time, so that the drain can empty the tub in t minutes and faucet Q can fill the tub in (t – 4) minutes. Also, the drain does negative work as it empties the tub. The rates for the pipes and the drain are thus

Using the fact that all three fixtures together take 6 minutes to fill 1 tub, set up an RTW chart, and use the chart to calculate the total work quantities (shown in boldface):

Set up an equation:

Multiply by the common denominator,

The negative value is absurd, so t = 10; the drain can empty the tub in 10 minutes.

A first-of-its-kind, on-demand MBA application experience that delivers a personalized curriculum for you and leverages interactive tools to guide you through the entire MBA application process.

### Upcoming Events

• Columbia J-Term (Round 2)
• Cambridge Judge (Round 1)
• HBS (Round 1)
• Penn Wharton (Round 1)
• Notre Dame Mendoza (Early Decision)
• Virginia Darden (Early Decision)
• Michigan Ross (Round 1)
• Columbia (Round 1)
• Stanford GSB (Round 1)
• Yale SOM (Round 1)
• Northwestern Kellogg (Round 1)
• Berkeley Haas (Round 1)