MATH 106 Name

Test 3 Take-home portion

Fall 2013/McKenzie

1. A mechanic and his apprentice were replacing the brakes on your car. The mechanic can complete a brake job in 6 hours, but the new guy needs 8 hours. They work together for the first 2 hours, but then the mechanic leaves for lunch.

How long will it take the new guy to finish fixing the car?

a) Write the equation you will use (and if it helps, draw a picture of what is happening, too):

b) Define your variables and givens:

c) Substitute these into the equation of part (a):

d) Write your final answer here, with units:

2. An inlet pipe can fill a barrel of vinegar in 8 hours and an outlet pipe can empty it in 12

hours. How long will it take to fill the barrel if both pipes are left open?

a) Write the equation you will use (and if it helps, draw a picture of what is happening, too):

b) Define your variables and givens:

c) Substitute these into and solve the equation in (a):

d) Write your final answer here, with units: