Twp cyclists start biking from a trails start 3 hours apart

Twp cyclists start biking from a trails start 3 hours apart. The second cyclist travels at 10 miles per hour and starts 3 hours after the first cyclist who is traveling at 6 miles per hour. How much time will pass before the second cyclist catches up with the first from the time the second cyclist started biking?

Solution

D=RT
D=6T
D=10(T-3)
6T=10(T-3)
6T=10T-30
6T-10T=-30
-4T=-30
T=-30/-4
T=7.5 HOURS THEY WILL MEET.
PROOF:
6*7.5=10(7.5-3)
45=10*4.5
45=45