Samantha drove 440 km in 5 hours. She drove part of the way at 80 km/h and the rest at 100 km/h. What distance did she drive at each speed?

Question

Samantha drove 440 km in 5 hours. She drove part of the way at 80 km/h and the rest at 100 km/h. What distance did she drive at each speed?

Answer 1

distance=rate*time

d=r*t

d(1)=80*t

d(2)=100*(5-t)

80t+100(5-t)=440

80t+500-100t=440

500-20t=440

500-440=20t

60=20t

t=3 hours

d(1)=80*3=240 km

d(2)=100(5-3)

d(2)=100(2)

d(2)=200 km

240+200=440