Answer:
6 hours
Step-by-step explanation:
because if they work together it will be 9 hours slower than Kelsey's time alone.
not sure if correct
Divide 7 by 8 then multiply what you get by 100.
Painter cost when he use the roller.
40:8=5 hours for painting 40 m²
5+1/2 =5 1/2 where 1/2 is time needed for clean upthe roller
total cost is
(5 1/2)*11=55+11/2=60.5 dollars
Painter cost when he use spray gun
40:20=2 hours for painting 40 m²
2+1=3 time with the time needed for clean up the spray gun
total cost is
3*11+5*3=33+15=48 dollars
60.5-48=12.5 dollars
You save is 12 dollars 50 cents