Question

A, B and C can do a piece of work in 80 days. If A is twice as efficient as B who is twice as efficient as C, then in how many days C alone takes to complete the work?

• A. 360
• B. 480
• C. 560
• D. 600

Answer 1

The correct option is C

560

Let the time taken by A to complete the work = x

The time taken by B to complete the work = 2x days

The time taken by C to complete the work = 4x days

If they work together

$\frac{1}{x}+\frac{1}{2x}+\frac{1}{4x}=\frac{1}{80}$

$x=140$

∴ Time taken by C to complete the work = 560 days