Quadratic Equations

Question

Ellie travelled 700km by truck to deliver some ostriches to her friend's farm, she then returned the same distance by car. The car averaged 10km/h faster than the truck and took 1 hour less time. what is the speed of the car? using the quadratic formula.

Answer 1

88.6 km/hr

d=rt

for the truck

700 = rt, with r= speed of the truck and t = time the truck took to go 700 km

700 for the car = (r+10)(t-1) = rt + 1-t - r -10 = 700 = rt for the truck

10t-r-10 = 0

r=700/t

10t - 700/t -10 = 0

multiply by t to get the quadratic

t^2 -t -70 = 0

use the quadratic formula to get

speed of the truck = about 8.9 hours

the car took 7.9 hours

700/7.9 = 88.6

Answer 2

700/t=s

700/(t-1)=(s+10)

Not enough imfo.