Question

Ritu and Mona can finish painting a house together in 18 days. Ritu alone would take 27 days to finish the painting. How long will it take Mona to finish the painting on her own?

• A. 65 days
• B. 60 days
• C. 44 days
• D. 54 days

Answer 1

Answer:

D. 54 days

Let the total work be 1 house.

Ritu’s rate = $( \frac{1}{27} )$ house/day

(Ritu + Mona)’s rate = $( \frac{1}{18} )$ house/day

So, Mona’s rate:

$\frac{1}{18} - \frac{1}{27}$

LCM of 18 and 27 = 54

$= \frac{3 - 2}{54} = \frac{1}{54}$

So, Mona alone can finish the painting in 54 days.