Hi All,

This question involves the Distance Formula and can be solved by TESTing VALUES.

Distance = (Rate)(Time)

We're told a few things about a kayaker:

1) She travels upstream at M km/hour

2) She travels downstream at N km/hour

3) Total TIME traveled is P hours

We're asked for the DISTANCE traveled UPSTREAM....

For this question, we're going to choose the two speeds AND the distance traveled....this will help us figure out the time traveled in each direction (and thus, the TOTAL TIME).

M = 2 km/hour upstream

N = 3 km/hour downstream

Distance = 6 km in each direction

Upstream:

D = (R)(T)

6km = (2km/hour)(T)

6/2 = T

T = 3 hours upstream

Downstream:

D = (R)(T)

6km = (3km/hour)(T)

6/3 = T

T = 2 hours downstream

P = TOTAL Time = 5 hours

We're asked for the DISTANCE traveled upstream, so we're looking for an answer that = 6 when M = 2, N = 3 and P = 5.

Answer A: (M)(N)(P) = (2)(3)(5) = 30 NOT a match

Answer B: MN/P = (2)(3)/(5) = 6/5 NOT a match

Answer C: (M+N)/P = (2+3)/5 = 5/5 NOT a match

Answer D: MNP/(M+N) = 30/5 = 6 This IS a MATCH

Answer E: PM/N - PN/M = 10/3 - 15/2 = Negative NOT a match

Final Answer:

GMAT assassins aren't born, they're made,

Rich

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# Rich Cohen

Co-Founder & GMAT Assassin

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