Question 428973
Let's take oscar's time as X.  Rico can drive twice as fast, or 2X.  Since rico arrives 2 hours earlier:

20/X =20/2X + 2
"""""=10/X + 2

Multiplying through by X we get:

20 = 10 + 2X
10 = 2X
5 = X

Oscar's speed is 5 mph.  Rico's speed is 10 mph