Solve the problem.
-Martha can rake the leaves in her yard in 2 hours. Her younger brother can do the job in 3 hours. How long will it take them to do the job if they work together?
A) $\frac { 6 } { 5 } \mathrm { hr }$
B) $6 \mathrm { hr }$
C) $\frac { 5 } { 6 } \mathrm { hr }$
D) $3 \mathrm { hr }$

Question

Solve the problem.
-Martha can rake the leaves in her yard in 2 hours. Her younger brother can do the job in 3 hours. How long will it take them to do the job if they work together? 
A) $\frac { 6 } { 5 } \mathrm { hr }$
B) $6 \mathrm { hr }$
C) $\frac { 5 } { 6 } \mathrm { hr }$
D) $3 \mathrm { hr }$

Quizplus · Accepted Answer

Martha's rate is 1/2 of the job per hour, and her brother's rate is 1/3 of the job per hour. Together, they can do (1/2 + 1/3) = 5/6 of the job per hour. Therefore, it will take them 1/(5/6) = 6/5 hours to complete the job together.

Solve the Problem 65hr\frac { 6 } { 5 } \mathrm { hr }56​hr

Solve the Problem $\frac { 6 } { 5 } \mathrm { hr }$