Luis can drive 3 times as fast as rico can ride his bike. If it takes rico 4 hours longer than Luis to travel 72 miles, how fast can ricoride his bike

Let Rico's speed be S

Then Luis' is: 3S

We then get: seventy-two over s equals seventy-two over three s plus four

216=72+12s Multiplying by LCD, 3S

216-72=12s

144 = 12S

S, or Rico's speed would be 144 over 12 or 12mph