Time and Work Practice Test 2 with solutions

Let time taken by A and B alone to finish the assignment is x and 2x respectively.
Work done by both in one day = $\frac{1}{\mathit{x}}+\frac{1}{2\mathit{x}}$
Now $\frac{1}{\mathit{x}}+\frac{1}{2\mathit{x}}$ = $\frac{1}{8}$
$\frac{2+1}{2\mathit{x}}$ = $\frac{1}{8}$
2x = 24
x = 12
So, A alone finish the given assignment in 12 days.