SOLUTION: Hi, I am having trouble figuring out how to solve this word problem. Sam fixes a car in 2 days, alex fixes a car in 4 days, and john fixes a car in 6 days. If all three work t

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Hi, I am having trouble figuring out how to solve this word problem. Sam fixes a car in 2 days, alex fixes a car in 4 days, and john fixes a car in 6 days. If all three work t      Log On


   

Question 225673: Hi,
I am having trouble figuring out how to solve this word problem.
Sam fixes a car in 2 days, alex fixes a car in 4 days, and john fixes a car in 6 days. If all three work together to fix the car, how long will it take?
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
they each do a FRACTION of the job based on their individual times and the combined time

FRACTION equals combined/individual ___ the FRACTIONS sum to 1, the WHOLE job

let x="combined time"

x/2 + x/4 + x/6 = 1

multiplying by 12 (LCD) ___ 6x + 3x + 2x = 12 ___ 11x = 12

dividing by 11 ___ x = 12/11