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?0.10.40.50.6

Answer Option 2  The part of the job that Marina can complete in 1 hourExplanationWorking 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