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jim can paint a house in 12 hours. alex can paint the same house in 8 hours. Enter an equation that can be used to find the time in hours, t, it would take alex and jim to paint the house together assuming they both work at the wages they work when working alone

jim can paint a house in 12 hours alex can paint the same house in 8 hours Enter an equation that can be used to find the time in hours t it would take alex and class=

Respuesta :

Answer:

it will take 4 hours for them to finish

Step-by-step explanation:

Answer:

4.8 hr, or 4 hr 48 min

Step-by-step explanation:

Let '1' represent 'the whole house-painting job.'

Then perform a dimensional analysis:

    1 whole house job

 -------------------------------- = 12 hours.   →This restates the obvious:  Jim can

          1 job/ 12 hrs                                     paint a house in 12 hours.

Now if both people work together, the total time required to paint the house is:

              1 house job                         1 house job

-----------------------------------------  =  ------------------------------  =  t for whole job

         1 job               1 job               8 job-hr + 12 job-hr        with both people

      ------------    +    ------------          -----------------------------       working

      12 hours           8 hours                        96 hr

This turns out to be:

              1

--------------------------  =  96/20 hr  = 4.8 hr, or 4 hr 48 min

      20/96