66 



FARM ARITHMETIC. 



things being equal, the selection of food materials should 

 take into account the comparative cost of digestible nutri- 

 ents. It may even happen that the cheapest food from 

 this standpoint is the more appetizing and otherwise de- 

 sirable when properly prepared. 



150. When oysters sell for 35 

 .•:?if^^?i^^::. cents per quart, 5.6 pounds are ob- 

 tained for $1. What amount of 

 digestible nutrients will this quan- 

 W^^M^^ ilf tity contain? 



'""'""•'''" 151. If, instead, you spend $1.00 



for beef loin, paying 20 cents per 

 pound for it, what quantity of 

 digestible nutrients do you receive? 



152. You spend $1.00 for wheat 

 flour, paying three cents per pound 

 for it. How many pounds of digestible nutrients do you 

 get? 



153. Finally you make a purchase of beans, the cost 

 of which is 5 cents per pound. What quantity of digesti- 

 ble nutrients do you obtain for $1.00? 



•Si 



a 



Growth of Bacteria. 



Showing the growth of 

 bacteria at different tem- 

 peratures during 24 hours, 

 each dot representing a 

 single bacterium. A, at 50 

 degrees, 7 bacteria; B, at 

 70 degrees, 700 bacteria. 



154. What quantity each of wheat flour, butter, eggs, 

 and whole milk will be required for daily food for a boy 

 and girl 14-16 years old ? 



