Working together, katherine and marina can sand a large cabinet in 2 hours. it would take katherine 10 hours to do the job alone. what is the value of r, the part of the job that marina can complete in 1 hour? 0.1 0.4 0.5 0.6

Answer

Option 2  

The part of the job that Marina can complete in 1 hour

Explanation

Working together, Katherine and Marina can sand a large cabinet in 2 hours.  

In hour the complete 1/2 of total work

It would take Katherine 10 hours to do the job alone.

In one hour Katherine complete 1/10 of total work

Let r, the part of the job that Marina can complete in 1 hour

So we can write,

r = 1/2 -1/10 = 0.4

The part of the job that Marina can complete in 1 hour is  0.4

step-by-step explanation:

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