22 FARM ARITHMETIC. 



by the value per pound we obtain the value on the basis of a ton. 



This is shown below: 

 Nitrogen, 1.6 X 20 = 32 32 ft @ 15c = $4.S ^ 



Phosphoric acid, 7 X 20 = 140 140 tb @ 5c = $7.00 



Potash, 2X20= 40 40 ft, @ 5c = $2.00 



Value of plant food, $13.80 



In this case $13.80 worth of plant food costs $30. 



65. What is the value of plant food in a ton of fac- 

 tory-mixed fertilizer containing 9 per cent of phosphoric 

 acid, 2 per cent of nitrogen and 2 per cent of potash? 



66. When a ton of such fertilizer sells for $28, what 

 is the money difference between its selling price to the 

 farmer and the money value of the plant food in it? 



67. What is the value of plant food in a ton of ferti- 

 lizer that contains 8 per cent phosphoric acid, 2 per cent 

 nitrogen, and 6 per cent potash? 



68. In a ton that contains 8 per cent phosphoric acid, 

 6 per cent nitrogen, and 2 per cent potash? 



69. The value of plant food in a ton of fertilizer is 

 $18. It analyzes 7 per cent phosphoric acid, 3 per cent 

 nitrogen. What per cent of this fertilizer is potash? 



70. Two commercial fertilizers are sold on the market. 

 No. 1 analyzes 5 per cent phosphoric acid, 3 per cent 



nitrogen, and 1}^ per cent potash and sells for $26 a ton ; 

 No. 2 analyzes 8^ per cent of phosphoric acid, 1 per 

 cent of nitrogen, and 2 per cent of potash and sells for 

 $25 a ton. In which fertilizer do you secure the greater 

 amount of plant food ? The better value ? 



71. If the No. 1 fertilizer rightly sells for $26 a ton, 

 on the same basis of plant food value, what can the 

 farmer afford to pay for No. 2? 



Note. — This difference arises from cost of manufacture, 

 agent's profits, and profits to manufacturer. When fertilizers 

 are mixed at home much of this difference can be saved. 



