Answer: a function is a relation between sets that associates to every element of a first set exactly one element of the second set. Typical examples are functions from integers to integers or from the real numbers to real numbers.
Since it's given Maggi buys 3/4 pounds of blueberry,it's means 3/4*1 .i.e. 0.75 pound and he uses 3/5 of 0.75 pound then it would be 3/5*0.75 .ie 0.45 pound