I drove to the beach at a rate of $40$ miles per hour. If I had driven at a rate of $55$ miles per hour instead, then I would have arrived $25$ minutes earlier. How many miles did I drive?
Rate * Time = Distance
Let T be the normal time in hours
25 minutes = 25/60 = 5/12 hr
Equate distances
40 T = 55 ( T - 5/12)
40T = 55T - 275 / 12
275 / 12 = 55T - 40T
275 / 12 = 15 T
275 / [ 12 * 15 ] = T
55/36 hrs = T
D = 40 (55 / 36) ≈ 61.1 miles
+1439 
