Question

Sandy can assemble a particular type of light fixture in 3/8 hour. it takes her 2/3 hour to hang the fixture and another 1/6 hour to wire the fixture once it is hung. how many fixtures could sandy install in 29 hours?

Answer 1

3/8 + 2/3 +1/6 = (18+32+8)/48 = 29/24

this means is takes Sandy 29/24's of an hour to install a fixture, or 1.20833 hrs per fixture.  divide 29 hrs by this number and you'll find she can install 24 fixtures.