Question 1195128

I am trying to figure out how to solve the following math problem:

Three people who work full time are to work together on a project, but their total time on the project is to be equivalent to that of only one person working full-time.  If one of the people is budgeted for one-sixth of his time to the project and a second person for one-half of her time, what part of the third worker's time should be budgeted for this project?

1. 1/8

2. 1/3
v3. 1/2

4. 3/4

The answer is 1/3.  I need to know the steps to arrive at that answer.
<pre>You don't have to spend all that time and put all that effort into this like that other person did - it's totally unnecessary. 

All this involves is: the whole project is one whole or just 1. 
1 person is budgeted for {{{1/6}}} of that whole, while the other is budgeted for {{{1/2}}}. 
This gives us: {{{highlight_green(matrix(1,9, 1 - (1/6 + 1/2), "=", 1 - (1/6 + 3/6), "=", 1 - 4/6, "=", 2/6, "=", 1/3))}}}</pre>