Question

A firm has two grades of coffee beans, Grade A and Grade B. 40 kg of Grade A and 45 kg of Grade B are to be mixed and packaged into two types of packets of 1 kg each — economy type and special type. The economy pack consists of beans of Grade A and Grade B in the ratio 1 : 3. The special pack consists of beans of Grade A and Grade B in equal proportion. Find the number of economy and special packs that can be made, using the substitution method.