
Patrick B. answered 05/27/20
Tutor
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Math and computer tutor/teacher
Sam workrate 1/5
Lucy workrate 1/3.5 = reciprocal of 7/2 = 2/7
combined workrate: 1/5 + 2/7 = 17/35
they will mow the lawn in 35/17 = 2 and 1/17 hours
2 hours 3 1/2 mins