Question 148046
when people work together on a task, they each do some FRACTION of the whole task


since working together takes less time than working alone
__ the combined time divided by an individual's time equals the fraction of the task that the individual completes


eg.  Bill can do a task in 9 hours __ when he works with a group, the task takes 3 hours
__ Bill does 1/3 (3/9) of the task


let x="time together" __ (x/4)+(x/3)=1 __ 1 is the whole task, the sum of the fractions


multiplying by 12 (LCD) __ 3x+4x=12 __ combining terms __ 7x=12 __ dividing by 7 __ x=12/7