It took Wally t minutes to commute to work in the morning. Due to rush hour traffic, his return trip took an extra 18 minutes. Given that the total time Wally spent in his car for both trips was 54 minutes, and that the distance between his home and office is 27 miles, determine the average speed for each leg.
Explain the answer :)

Question

It took Wally t minutes to commute to work in the morning. Due to rush hour traffic, his return trip took an extra 18 minutes. Given that the total time Wally spent in his car for both trips was 54 minutes, and that the distance between his home and office is 27 miles, determine the average speed for each leg. 
Explain the answer :)

anonymous · Answer

d=vt
t=d/v
t1, v1 to work
t2,v2 to home
t1+18=27/v2
t2=27/v2
27/v2-18+27/v2=54
v2=.75 mi/min *60 min/hr = 45mi/hr
At this speed, the time required would be t2=d/v=27/45=3/5 hr or 36 minutes.
t1=t2-18=36-18=18
v1=d/t1=27mi/18min=1.5mi/min*60min/1hr=90mi/hr

anonymous · Answer

i forgot to put in that t2=t1+18

aroub · Answer

Wait, you have to work with me a bit.. What did you exactly do here: t1+18=27/v2 ?

anonymous · Answer

That's where I forgot to put t2=t1+18, time 2=time 1+18

anonymous · Answer

so t1=t2-18

anonymous · Answer

i then added t1 and t2 to get 54 minutes in terms of v2, the average speed home

anonymous · Answer

it is kind of messy, lol

aroub · Answer

Haha, it's okay. I got it! Thank you =DD

hero · Answer

|dw:1329253473501:dw|
2t + 18 = 54
2t = 54 - 18
2t = 36
t = 36/2
t = 18