Davie and horatio are riding their motorbikes on a scenic tour that is 80 miles long. davie rides at 20 miles per hour and leaves 90 minutes before horatio. how fast must horatio ride to finish at the same time as davie?
a 24 mph
b 24.5 mph
c 32 mph
d 33.3 mph

C 32, Dave will take 80/20 = 4 hours to finish.  Horatio only has 2 and a half hours to cover the same distance (80 miles).  80/2.5 = 32

16 minutes is correct

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.