A, B and C can complete a work in 7 days. If A and B complete the work together, they take 10 days. How much time will C take in completing the work alone?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 23.33 days
Work is added through the work done in one day: the day’s work of A, B and C together, less the day’s work of A and B, is the day’s work of C alone.
A, B and C in one day: \(\frac{1}{7}\) of the work
A and B in one day: \(\frac{1}{10}\) of the work
C in one day: \(\displaystyle\frac{1}{7}-\frac{1}{10}=\frac{10-7}{70}=\frac{3}{70}\)
C alone takes \(\displaystyle\frac{70}{3}=23\frac{1}{3}\approx23.33\) days