Question 168440
9.5 = 10 when rounded to the nearest unit.

11.5 = 12 when rounded to the nearest unit.

Let x represent the time it takes for both of them, working together, to finish the job.

x/10 + x/12 = 1

To clear the fractions, multiply each term by the LCD, which so happens to be 60.

Doing so, we get this equation:

6x + 5x = 60

11x = 60

x = 60/11

x = 5.45

It would take them 5.45 hours to do the job together.