25. Tom and Jerry must stuff and mail 1000 envelopes for a new marketing campaign. Jerry can do the job alone in 6 hours. If Tom h

Question

25. Tom and Jerry must stuff and mail 1000
envelopes for a new marketing campaign. Jerry
can do the job alone in 6 hours. If Tom helps,
they can get the job done in 4 hours. How long
would it take Tom to do the job by himself?
A. 4 hours
B. 5 hours
C. 8 hours
D. 12 hours​

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Melanie 2 weeks 2021-09-11T00:10:59+00:00 2 Answers 0

Answers ( )

    0
    2021-09-11T00:12:11+00:00

    Answer:

    12

    Step-by-step explanation:

    The general formula for this is

    Formula

    1/t1 + 1/t2 = 1/t_tot

    givens

    t1 = 6 hours

    t2 = x

    t_tot = 4 hours

    Solution

    1/6 + 1/x = 1/4                 Subtract 1/6 from both sides.

    1/6-1/6 + 1/x = 1/4 – 1/6   Change to 12 as your common denominator

    1/x = 3/12 – 2/12              subtract

    1/x = 1/12                         Cross multiply

    x = 12

    Tom would need 12 hours to do the job alone.

    0
    2021-09-11T00:12:57+00:00

    Answer:

    Option D. 12 hours

    Step-by-step explanation:

    Let the work done by Tom to do the job alone = x hours

    So per hour work done by Tom = \frac{1}{x}

    Jerry can do the job alone in the time = 6 hours

    Per hour work done by Jerry = \frac{1}{6}

    Similarly job done by both together in the time = 4 hours

    Per hour work done by both together = \frac{1}{4}

    Now we know,

    Per hour work done by both together = per hour work done by Tom + Per hour work don by Jerry

    \frac{1}{4}=\frac{1}{x}+\frac{1}{6}

    \frac{1}{x}=\frac{1}{4}-\frac{1}{6}

    \frac{1}{x}=\frac{3-2}{12}

    \frac{1}{x}=\frac{1}{12}

    x = 12 hours

    Option D. will be the answer.

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