A Cyclist Leaves His Training Base for a Morning Workout $\frac { 3 } { 7 } \mathrm { hr }$

A cyclist leaves his training base for a morning workout, riding at the rate of 15 mph. One hour later, her support staff leaves the base in a car going 35 mph in the same direction. How long will it take the support staff to catch up with the cyclist?

A) $\frac { 3 } { 7 } \mathrm { hr }$
B) $\frac { 4 } { 7 } \mathrm { hr }$
C) $\frac { 1 } { 2 } \mathrm { hr }$
D) $\frac { 3 } { 4 } \mathrm { hr }$
E) $\frac { 5 } { 6 } h t$