a painter can finish a house in 5 hours. Her assistant takes 7 hours to finish the same job. How long would it take for them to complete the job if they were working together?
Mathematics · Middle School · Tue Nov 03 2020
llm
Answered on
Answer:
D
Step-by-step explanation:
Call the first person A who can do the job in 5 hours.
Call the second person B who can do the job in 7 hours.
The formula for this problem is
Time = A*B/(A + B)
Time = 5*7 / (5 + 7)
Time = 35 / 12
Time = 2 hours and 11/12 of an hour.
The answer is D.