Problema Solution
Bill drove from San Antonio, TX, to Austin, TX, a distance of 75 miles. Then he continued on to Dallas, TX, a distance of 195 miles. If he drove 10 mph faster from San Antonio to Austin and the total time of the trip was 6 hours, find his average speed from San Antonio to Austin. Give the answer to two decimal places
Answer provided by our tutors
let his speed from san antino to austin = x miles/hr
time = 75/x hour
speed from austin to dallas = x+ 10 miles/hr
time = 195/(x+10)
total time = 75/x + 195/(x+10)
=> 75/x + 195/(x+10) = 6
=> x^2 - 35x - 125 = 0
=> x = 38.27 miles/hr
average peed from san antino to austin = 38.27 miles/hour