Question 1174482
A contractor finds that Crew A takes 5(1/2) hours to construct a retaining wall and Crew B can do the same job in 7(1/2) hours.
 If Crew A and Crew B work together, how long will it take them to construct the retaining wall?
a) Let h = the time to complete the job. Write the equation you would use to solve this problem.
:
let the completed job = 1, each will do a fraction of the job which adds up to 1
{{{h/5.5}}} + {{{h/7.5}}} = 1
:
b) Now solve your equation. Give your answer first as a reduced fraction, and then a decimal rounded to 3 places.
Multiply eq by 5.5*7.5 = 41.25, cancel the denominators
7.5h + 5.5h = 41.25
13h = 41.25
h = 41.25/13
h = 3.173 hrs working together