Tank A is filling up with water at a rate of 5/8 gallon per 1/2 minute. Tank B is filling with water at a rate of 3/5 gallon per 1/4 minute. Which tank is filling faster?

Compute the unit rates.

Tank A:

(5/8 gal) / (1/2 min) = 10/8 gal/min = 5/4 gal/min = 1.25 gal/min

Tank B:

(3/5 gal) / (1/4 min) = 12/5 gal/min = 2.2 gal/min

So tank B is filling faster.