1/x + 1/y + 1/z + … = 1/t

Where t the time it takes for everyone and x, y, z, etc. is the time for one person.

Now lets plug in the formula.

1/x + 1/y = 1/15

Now y takes twice as long as x so y = 2x Therefore,

1/x +1/2x = 1/15. Multiply by x gives

1 + 1/2 = x/15

x = 22.5

y = 2x = 45.

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That is the general formula; This problem is simpler. Since Jim is twice as fast as Jack therefore Jim = 2 Jacks.

3 Jacks take 15 hours. Therefore it is obvious that one Jack would take 3 times as long or 45 hours.

Jim working twice as fast takes only half that time or 22.5 hours.

secondly, you are going about this the wrong way. they BOTH WORK for 15 hours.

15 hours= 30 “man hours”

I’ll leave you to figure out the rest of that

and the second part is NO. any extra help would make it go faster.

http://workathomedataentryworkss.blogspot.com

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