I drove to the beach at a rate of 40 miles per hour. If I had driven at a rate of 50 miles per hour instead, then I would have arrived 45 minutes later. How many miles did I drive?
D==Distance to the beach.
T ==Time it takes you to drive to the beach at 40 mph
D / 40 ==T.....................(1)
D / 50 ==T - 45/60........(2), solve for D, T
D==150 miles
Note: If you drive at 50 mph, you would arrive 45 minutes EARLIER and not "later" !!
+8 t2 - t1 = 0.75
(d / 50) - (d / 40) = 0.75
To solve this equation, let's find a common denominator for the fractions:
(40 * d) / (40 * 50) - (50 * d) / (50 * 40) = 0.75
(40d - 50d) / 2000 = 0.75
(-10d) / 2000 = 0.75
Multiplying both sides by 2000:
-10d = 0.75 * 2000
-10d = 1500
Dividing both sides by -10:
d = 1500 / -10
d = -150
