A park manager wants to fertilize an area of turfgrass with nitrogen and phosphorus at the rates of 60 kg/ha of N and 20 kg/ha of P. He has stocks of two types of fertilizers: urea (labeled...

A park manager wants to fertilize an area of turfgrass with nitrogen and phosphorus at the rates of 60 kg/ha of N and 20 kg/ha of P. He has stocks of two types of fertilizers: urea (labeled 45-0-0) and diammonium phosphate (labeled 18-46-0). How much of each should he blend together to fertilize a 10-ha area of turfgrass?