carl drove from his home to the beach in an avg speed of 80 km per hr and returned home at avg speed of 70 km/hr. he spent 1/2 hour longer to come back home. how many km did he drive each way?
OA: 280
OA: 280
Average speed= total distance/total time.
Let's assume that the distance from Carl's home to the beach was y miles and that it took Carl x hours to travel those y miles when going to the beach. So:
y/x=80
x=y/80
The problem tells us that it took Carl 1/2 an hour longer when coming back home. So:
y/x+1/2=70
y=70x+35
Plug in x=y/80 and solve for y.
y=7y/8+35
y/8=35
y=280
