Answered

Working together ali and rj can paint a wall in 3hrs. Working alone, ali can do the job in 5hrs. How long will it take rj to finish the job?

Sagot :

15x[1/x+1/5=1/3]15x
15x/x+15x/5=15x/3
15+3x=5x
15=5x-3x
15=2x
 2   2
7.5=x
7.5 hours