Question

If Art and Rita can do a job in 4 hours when working together at their respective constant rates and Art can do the job alone in 6 hours, in how many hours can Rita do the job alone ?

• A. 10
• B. 12
• C. 8
• D. 14

Answer 1

Answer: (B)

12

$\frac{1}{6}+\frac{1}{R}=\frac{1}{4}$

$\frac{R+6}{6R}=\frac{1}{4}$

$4R+24=6R$

$24=2R$

$12=R$

Working alone, Rita can do the job in 12 hours. (option B)