1 53-' 



The Cornell Reading-Courses 



of fat in the materials to be mixed. Subtract the number in the center 

 from the larger number at the left of the rectangle. Place the remainder 

 on the diagonally opposite right-hand comer of the rectangle. Subtract 

 the smaller number on the left-hand corner from the number in the center 

 and place the remainder on the diagonally opposite right-hand corner of 

 the rectangle. 



The two numbers on the right-hand comers of the rectangle represent 

 the number of pounds of material required. If these two numbers are 

 added they will express the number of pounds of the mixture, which will 

 contain a percentage of fat expressed by the number in the center of the 

 rectangle. In each case the number on the right-hand corner corresponds 

 in fat test to the number on the left-hand corner directly opposite. 



Problem 8: 



How many pounds of 40-per cent cream and 3 -per cent milk must be 

 mixed to make a milk testing 5 per cent ? Using our diagram as described 

 above we have the following result : 



This means that if 2 lbs. of 40% cream are mixed with 35 lbs. of 3% 

 milk, the result will be a 37-lb. mixture testing 5%. Answer. 



Problem p: 



How many pounds of 28-per cent cream and 3 -per cent milk will be 

 required to make 500 pounds of a mixture testing 4 per cent? In this 



problem a definite number of pounds of the 

 mixture is required. 



According to the diagram, i lb. of 28% 

 cream is required to every 24 lbs. of 3% milk 

 to make a mixture testing 4%. This would 

 make 25 lbs. of the mixture, but 500 lbs. is the 

 amount desired. In other words, the number 

 of pounds desired is 20 times larger than the number of pounds on hand 

 (500 -^ 25 = 20). The amounts must be kept in the proportion of i : 24. 

 Therefore, in order to get a 500-lb. mixture it is necessary to multiply 

 both the I and the 24 by 20. This would give a result of 20 lbs. of 28% 

 cream and 480 lbs. of 3% milk, which mixed will equal 500 lbs. of 4% 

 milk. Answer. 



