"Traffic Jam" Math problem for college algebra 98.?
"Betty Truitt drives for a number of hours at 70 miles per hour. When traffic slows, she drives at 50 miles per hour. She travels at 50 miles per hour for 0.5 hour longer than she traveled at 70 miles per hour. The difference in the distance traveled at 50 mph and 70 mph is 5 miles. Determine how long Betty traveled at 50 miles per hour."
Comments
let
x = time in hours travelled at 70 mph
70x = d
50(x + .5) = di
di - d = 5
50(x + .5) - 70x = 5
50x + 25 - 70x = 5
-20x = -20
x = 1
she travelled for 1 + .5 =
1.5 hours at 50 mph
1 hour at 70 mph
Traffic Jam Math Problem