36 A Handbook for Dairymen 



Working the problem by the rectangle method 

 (see page 32), 1 part of 28 per cent cream is re- 

 quired for 24! parts of 3 per cent milk. According 

 to the terms of the problems, 150 pounds of 28 per 

 cent cream must be used, and the 3 per cent milk 

 must be increased 160 times. This would give 150 

 pounds of 28 per cent cream (IX 150), and 3600 

 pounds of 3 per cent (150X24 = 3600), making 

 in all 3750 pounds (160 + 3600 = 3750) of a 4 per 

 cent mixture. 



This problem may also be worked by simple pro- 

 portion : 



24 : 1 : : X : 150 



x^3600, the number of pounds of 3 per 



cent milk required.- 



Proof. 



The 3750 pounds of 4 per cent milk will contain 

 150 pounds of fat (3750 X .04 = 150). If the 150 

 pounds of 28 per cent cream and 3600 pounds of 

 3 per cent milk furnished 150 pounds of fat, the 

 problem is correct. 



3600 X .03 = 108, number of pounds of fat 

 in milk. 



150 X .28 =1 42, number of pounds of fat in 

 cream. 



108 + 42 = 160, number of pounds of fat in 

 mixture. — Answer. 



