Question

A and B can do a piece of work in $8$ days and
$12$ days respectively. How long will they take
to finish it they work together?

• A. $2\frac{3}{5}$ days
• B. $4\frac{4}{5}$ days
• C. $5\frac{4}{5}$ days
• D. none of there

Answer 1

The correct option is B $4\frac{4}{5}$ days

$A\to 8$ days $;B\to 12$ days.

speed of $A\to \frac{x}{8};$ speed of $B\to \frac{x}{12}.$

$\therefore A+B\to \frac{x}{8}+\frac{x}{12}=\frac{3+2}{24}x=\frac{5}{24}x$

$\therefore$ No. of days required $=\frac{24}{5}=4\frac{4}{5}$ days