Martha takes a road trip from point A to point B. She drives x percent of the distance at 60 miles per hour and the remainder at 50 miles per hour. If Martha's average speed for the entire trip is represented as a fraction in its reduced form, in terms of x, which of the following is the numerator?
Ans. = E
average rate = d/t
t = [ (x/100)*d/60 + (1- x/100)*d/50]
= [ x/6000 + (100-x)/5000]*d
The least common denominator of t is 30,000.
Thus, average rate = d/t has the numerator of 30,000 as the reduced number since 30,000 is the least common denominator of t.