Question

A man drove to work at an average rate of speed 60 miles per hour and

Answer 1

let x = miles

we have x miles/ 60mph plus x miles / 40 mph = 1 hour

x/60 + x/40 = 1

 we need to calculate 2x for the round trip

calculate common denominator and rewrite the 2 fractions:

2x/120 + 3x/120 = 1

5x= 120

x = 120/5 = 24 miles

24*2 = 48 miles total

 check:

 1 way would be 48/2 = 24 miles

24/60 = 0.4 hours to drive 24 miles at 60 mph

24/40 = 0.6 hours to drive 24 miles at 40 mph

0.6 +0.4 = 1 hour