Question 77739
Distance(d) = rate(r) times time(t) or d=rt, t=d/r and r=d/t

We are told that the speed (rate) on both days are the same

Let t=driving time on the second day of trip
Then t+2=driving time on first day of trip

Rate on  second day=270/t

Rate on first day=360/(t+2)

But we are told that:

Rate on second day=rate on first day, so

270/t=360/(t+2)  multiply both sides by t(t+2) to get rid of fractions

(270(t)(t+2))/t=(360(t)(t+2))/(t+2)  simplify

270(t+2)=360t  get rid of parens

270t+540=360t  subtract 270t from both sides

360t-270t=270t-270t+540  collect like terms

90t=540  divide both sides by 90

t=6 hours-------------------driving time second day

t+2=6+2=8 hours----------------------driving time first day

ck

r=d/t

r=360/(6+2)=360/8=45 mph

r=270/6=45 mph



Hope this helps-----ptaylor