Problema Solution
Billy wants to know how much to charge for mowing your neighbor's yard. His price is $10 an hour and his mowing speed is .2 yards per second. What would the total cost be if the house is 10 feet by 10 feet and the yard is 20 feet by 20 feet?
Answer provided by our tutors
the speed of Billy is v = 0.2 yards^2 per second
since 1 yard = 3 feet or 1 yard^2 = 9 ft^2 we can write v = 0.2*9 = 1.8 ft^2/sec
lets find the mowing area: 10*10 + 20*20 = 100 + 400 = 500 ft^2
the time that Billy will need to mow 500 ft^2 is: 500/v = 500/1.8 = 277.8 s = 277.8/3600 h
since he is charging $10 an hour for 277.8/3600 h he will need to charge 10*(277.8/3600) = $0.77 for mowing the area of 500 ft^2.