I need help on this word problem

[cluelesschloe]

I really need help on this word problem: David traveled 120 miles in 1 hour less than it took Emily to travel 360 miles. Emily could do this because she drove twice as fast as David. Find the rates and times of both. :?: [/b]

 

[galactus]

Let r = rate of Dave.

He travels 120 miles in 1 hour less than it takes Emily to drive 360 miles.

Emily drives twice as fast as Dave. Emily's rate is 2r.

\(\displaystyle \L\\r(t-1)=120\)
\(\displaystyle \L\\2rt=360\)

Solve for r and t.