Question

A works twice as fast as B. If B can complete a work in 24 days independently, the number of days in which A and B can together finish the work is?

• A. 12 days
• B. 9 days
• C. 8 days
• D. 6 days
• E. None of these

Answer 1

The correct option is C 8 days



(The no. of days is indirectly proportional to the efficiency)
Now, given that,
$2x=24$
$x=12days$

The number of days in which A and B can together finish the work
$=\frac{2x\times x}{2x+x}$
$=\frac{2x}{3}$
$=8days$