A farm used two harvesting machines, H and K, to harvest 100 acres of wheat. Harvesting machine H, working alone at its constant rate, harvested 40 acres of wheat in 8 hours. Then harvesting machine K was brought in, and harvesting machines H and K, working together at their respective constant rates, harvested the remaining acres of wheat in 3 hours. Harvesting machine K harvested how many acres of wheat per hour? Select:
A) 7 B) 8 C) 12 D) 13 E) 17
Rate of H = 3 acres/hr   Remaining land to be harvested = 100 - 40= 
<gadget id="calculator">100 - 40</gadget>
<output>60</output>
60   Rate of H and K= 60/3= 
<gadget id="calculator">60/3</gadget>
<output>20</output>
20 acres/hr   Rate of K= 20-3= 
<gadget id="calculator">20-3</gadget>
<output>17</output>
17   Answer: 17
<result>E</result>
A farm used two harvesting machines, H and K, to harvest 100 acres of wheat. Harvesting machine H, working alone at its constant rate, harvested 40 acres of wheat in 8 hours. Then harvesting machine K was brought in, and harvesting machines H and K, working together at their respective constant rates, harvested the remaining acres of wheat in 3 hours. Harvesting machine K harvested how many acres of wheat per hour?