27 and |-27| are not opposites. The lines in -27 are the absolute value, which is always positive. 27 and 27 are not opposite. They are the same. The 3rd choice is the answer.
1)
We calculate the total number of new light fixtures.
Total number of new light fixtures=(24 new fixtures/1 floor)(4 floors)=
=96 new fixtures.
2)
We calculate the total number of work hours
20 minutes=20 minutes * (1 hour/60 minutes)=1/3 hour.
1 electrician-----------1/3 hour----------1 new fixture
2 electricians---------- x ------------96 new fixtures
1 elec.*1/3 hour*96 nex fixtures=2 elect. * x * 1 new fixture.
x=(1 elec. *1/3 hour * 96 nex litght fixtures) / (2 elect.* 1 new fixture)=
=16 hours.
3)
We calculate the total number of days that it take two electricians to complete the installations.
1 day-------------8 work hours
x------------------16 work hours
x=(1 day* 16 work hours) / (8 work hours)=2 days
Answer: 2 days.