Add Rates for Combined Rate: Add their rates together to find their combined rate.Combined rate = Henry's rate + Nathan's rate = 0.5hourlawn+0.4hourlawn=0.9hourlawn.
Calculate Time for Mowing: Calculate the time it takes for them to mow the lawn together.Time = Combined rate1 lawn=0.9 lawn/hour1 lawn=1.111… hours.
More problems from Ratios and rates: word problems