drive time 10

Question

Bob drove from home to work at 50
mph. After work the traffic was? heavier, and he drove home at 30
mph. His driving time to and from work was 1
hour and 4
minutes. How far does he live from his? job?

Answer 1

Let t = time driving at 50mph & T = time driving at 30 mph.

Total T + t = 1:04 (hr:min) or 1.066666 hr.

 

D = 50(t) so t = D/50

D = 30(t) so T = D/30.

 

T+t = 1.066666 = D/50+D/30

 

1.066666 = D(1/50+1/30)

1.066666 = D(0.0533333)

 

D = 20 miles.

Answer 2

t=time; d=distance home to work; s=speed

s1=50 m/h= 50/60 m/min; s2=30/60 m/min

t=d/s= d/s1+d/s2= 64 min

d= 20 millas