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March 30, 2015

March 30, 2015

Posted by **Paige** on Wednesday, March 2, 2011 at 6:55pm.

Sammy can cut wood twice as fast as Joe. When they both work together, it takes them 4 hrs. how long would it take them to do the job alone?

4/x +4/x+2 = x^2+2

4x+4x+8= x^2+2

8x+8= x^2+2

x^2-6x-8=0

(x-4)(x+2)

x=4 x=-2 since i can't use a -2 i have to put in a 4

x+2=4+2=6

Sammy =6 hours

6x2=12

Joe = 12 hours

Thanks

- Algebra 2 word problem -
**Reiny**, Wednesday, March 2, 2011 at 7:59pmJoe's rate ---- 1/2x

Sammy's rate --- 1/x

combined rate = 1/x + 1/2x = 3/(2x)

time to do job with combined rate = 1/(3/(2x)) = 2x/3

but we know that is 4 hrs

2x/3 = 4

2x=12

x = 6 and then 2x = 12

So Sammy could do it 6 hours

and Joe would take 12 hours.

- Algebra 2 word problem -
**Reiny**, Wednesday, March 2, 2011 at 8:04pmBTW, I won't even begin to point out all the errors in your solution.

Your opening equation makes no sense, and has no relation to the question.

the 2nd line does not follow from the 1st line

your "solution" of x=4 does not even satisfy your opening equation , as it should.

It looks like you knew what the answer was supposed to be, and simply formed some expression that contain that answer.

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