Help me solve this Algebra problem

[MechaSheeba]

It's been way too long since I've done this sh!t...

I need the formula to solve a problem like this:

If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days, how long would the job take if Sam, Lisa, and Tom worked together to complete it?

What's the formula? The answer is 1.09 days btw, if that helps any of you other rusty ppl figure out how to set up the equation..

EDIT: Oops I think I might've dicked up the wording, let's try this one instead.

 

[Aquaman]

47 or C (for multiple choicec tests) 😉

Cheers,
Aquaman

 

[Fenixgoon]

in 15 minutes they can eat X + 3x + 1.5x = 5.5x pies

 

[randay]

They need to get thier fat asses some excercise, eating all those pies all the time.

 

[MechaSheeba]

Heh, I think I fvcked it up making up my own problem so I'm just gonna use the example they gave me.

 

[RapidSnail]

First set up values.

let x = total days working together

1/4 = Sam's rate per day

1/6 = Lisa's rate per day

1/2 = Tom's rate per day


Then fill in the blanks


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

12[x(1/4 + 1/6 + 1/2)] = 12(1)

3x + 2x + 6x = 12

11x = 12

x = 1.09...


Solution

If Sam, Lisa, and Tom worked together, they would complete the job in approximately 1.09 days.

 

[HBalzer]

i don't know but they need to fire that chick and give tom a raise

 

[The Pentium Guy]

47 or C (for multiple choicec tests)

I get the C part but where and how do you get 47 😛.

 

[dullard]

Originally posted by: RapidSnail
If Sam, Lisa, and Tom worked together, they would complete the job in approximately 1.09 days.

No, you got it all wrong. There is no way Tom could keep uo that great pace when the attractive Lisa comes to work with him! In fact, Lisa may or may not be distracted by Sam. Thus, they'll work far slower than that.

I know it isn't math here, but I like to add a dose of reality.

 

[MechaSheeba]

Originally posted by: RapidSnail
First set up values.

let x = total days working together

1/4 = Sam's rate per day

1/6 = Lisa's rate per day

1/2 = Tom's rate per day


Then fill in the blanks


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

12[x(1/4 + 1/6 + 1/2)] = 12(1)

3x + 2x + 6x = 12

11x = 12

x = 1.09...


Solution

If Sam, Lisa, and Tom worked together, they would complete the job in approximately 1.09 days.

Cool, I got it now, thanks.

 

[HBalzer]

If they fire Lisa they can still get it done in about 1.33 days plus there will be fewer interruptions. Then they use the money they would have paid Lisa as inceptive for Tom and Sam to get the job done in 1 day and everyone but Lisa wins.