Problema Solution
On the first day of a two day vintage car rally, Mr. and Mrs. Harrington drove 90 miles in their
1940 Chevrolet Cabriolet. On the second day they were able to average 20 mph faster
by driving their 1968 Ford Mustang, and they traveled a total of 100 miles. If the total driving
time for the two days was 5 hours, what was their average speed in each of the vehicles?
Answer provided by our tutors
let
d1 = 90 mi
v = the average speed of the first day
d2 = 100 mi
v + 20 = the average speed on the second day was 20 mph faster then on the first day
t = 5 hr the total driving time for the two days
since avg.speed = total distance/time => time = total distance/avg.speed
v/d1 + (v + 20)/d2 = 5
v/90 + (v + 20)/100 = 5
by solving the equation we find
v = 227.37 mph
click here to see the step by step solution of the equation
v + 20 = 247.37 mph
the average speed on the first day in the 1940 Chevrolet Cabriolet was 227.37 miles per hour.
the average speed on the second day in the 1968 Ford Mustang was 247.37 miles per hour.