Question

Answer ASAP!
Sergei can reorganize the library in 5 hours. His sister Irina can do the job in 10 hours. How long would it take for the two of them to do the job together?

Answer 1

Answer:

Step-by-step explanation:

The productivity of Sergei's work is $\frac{1}{5}$

The productivity of Irina's work is $\frac{1}{10}$

Sergei and Irina would complete the work in "x" hours and the productivity of their work together is $\frac{1}{x}$ from one hand and ( $\frac{1}{5}$ + $\frac{1}{10}$ ) from another hand.

$\frac{1}{x}$ = $\frac{1}{5}$ + $\frac{1}{10}$ ⇔ $\frac{1}{x}$ = $\frac{3}{10}$ ⇒ x = 10 ÷ 3

Together Sergei and Irina can reorganize the library in $3\frac{1}{3}$ hours.