Today Dave drove from home to work at twice his regular speed and arrived at work 16

[Brent@GMATPrepNow]

Today Dave drove from home to work at twice his regular speed and arrived at work 16 minutes earlier than he regularly arrives. If Dave regularly drives at a constant speed of 40 miles per hour, what is the distance, in miles, from Dave’s home to work?

(A) 16/3
(B) 32/3
(C) 40/3
(D) 64/3
(E) 80/3

Answer: D
Source: www.gmatprepnow.com

[Brent@GMATPrepNow]

Today Dave drove from home to work at twice his regular speed and arrived at work 16 minutes earlier than he regularly arrives. If Dave regularly drives at a constant speed of 40 miles per hour, what is the distance, in miles, from Dave’s home to work?

(A) 16/3
(B) 32/3
(C) 40/3
(D) 64/3
(E) 80/3

Answer: D
Source: www.gmatprepnow.com

Dave's regular driving speed = 40 mph
Dave's driving speed TODAY = 80 mph

Let d = the distance from Dave's home to work

Dave arrived at work 16 minutes earlier than he regularly arrives.
We can write: regular travel time in hours - 16/60 hours = today's travel time in hours

time = distance/rate, which means we can write: d/40 - 16/60 hours = d/80
Rewrite each fraction with denominator 240 to get: 6d/240 - 64/240 hours = 3d/240
Multiply both sides of the equation by 240 to get: 6d - 64 = 3d
Subtract 6d from both sides: -64 = -3d
Divide both sides by -3 to get: 64/3 = d

Answer: D