Solve the Problem $\frac{9}{14} \mathrm{hr}$ B) $\frac{14}{5} \mathrm{hr}$ C) $\frac{14}{9} \mathrm{hr}$ D) $7 \mathrm{hr}$

Multiple Choice

Solve the problem.
-Martha can rake the leaves in her yard in 2 hours. Her younger brother can do the job in 7 hours. How long will it take them to do the job if they work together?

A) $\frac{9}{14} \mathrm{hr}$
B) $\frac{14}{5} \mathrm{hr}$
C) $\frac{14}{9} \mathrm{hr}$
D) $7 \mathrm{hr}$