Thread: Small Math Word Problem-Help!!!

Jim takes twice as long as Karen to do a task. If working together they can do the task in 5 hours, how long does it take Jim to complete the task alone?

a)7.5 hours
b)6 hours
c)15 hours
d)10 hours
e)impossible to determine from the given information

Can anyone explain to me how to work this out?
Help me please!!!!

in 5 hrs, both do 2.5 hrs of work each.

karen does twice the work of jim, so karen does 2/3 of the work in 2.5 hrs
and jim does 1/3 of the work in 2.5 hours.

jim takes 3(2.5 hrs) = 3(1/3 of the job) to do all the work himself.

so what's the answer?

didn't you bother to read my post?

the "answer" is there ... you find it.

I did, but you didn't clearly state your answer. (like a, b, c, etc.)
I had the answer choices listed above. I would have liked it if you put one down, because that was quite confusing. anyway, the answer is 15, so thank you anyway for your help.

....by my reckoning the answer is 7.5 hrs

3(2.5) time = 3(1/3) work = 3/3 work = all work = 3X2.5 time = 7.5 time

I came up with A too 7.5

2x=5

5/2

= 2.50 - 9.00 = 7.5 hrs ;p

that's how I did it.

I was wrong. The correct answer is 15 hrs.

they worked together for 5 hrs, not separately as I first thought ... karen does 2/3 of the job and jim does 1/3 of the job.

if it takes jim 5 hrs to do 1/3 of the job, then it will take him 15 hrs to do the whole job by himself.