The distance between two cities is ninety miles, and a woman drives from one city to the other at a rate of 45 mph. At what rate must she return if the total travel time is three hours and forty minutes?

Question

agent47 · Answer

90/45mph=x(h)

agent47 · Answer

90/v=x+x1

agent47 · Answer

x+x1=225 mins

agent47 · Answer

Time to get to the city was 2 hours. So she has to get back in 1 hours and 40 mins

anonymous · Answer

it took her $\frac{90}{45}=2$ hours to get there. she has only 1 hour and 40 minutes or $1\tfrac{2}{3}$ hours left to make the return trip.  
to get the rate, divide the distance by the time. i.e divide 
$$90\div 1\tfrac{2}{3}$$

agent47 · Answer

well I'll finish what I was saying, though someone got there first

anonymous · Answer

$$90\div 1\tfrac{2}{3}=90\div \frac{5}{3}=90\times \frac{3}{5}$$

agent47 · Answer

ok I won't finish what I was saying lol