Two persons A and B take a field on rent. A puts on it 21 horses for 3 months and 15 cows for 2 months; B puts 15 cows for 6months and 40 sheep for 7 1/2 months. If one day, 3 horses eat as much as 5 cows and 6 cows as much as 10 sheep, what part of the rent should A pay?	Choose the correct choice from the following choices.
A) 1/3
B) 1/5
C) 1/0
D) 1/2
E) 1/1
3h = 5c   6c = 10s   1/3 = 21h*3 + 15c*2   = 63h + 30c   = 105c + 30c = 135c   B 105  + 30= 
<gadget id="calculator">105  + 30</gadget>
<output>135</output>
135c   B= 15c*6 + 40s*7 1/2   = 90c + 300s   = 90c + 180c = 270c   1/3:B 90  + 180= 
<gadget id="calculator">90  + 180</gadget>
<output>270</output>
270c   1/3:B= 135:270   27:52   1/3 = 27/79 = 1/3   1/3nswer: 1/3
<result>A</result>
Two persons A and B take a field on rent. A puts on it 21 horses for 3 months and 15 cows for 2 months; B puts 15 cows for 6months and 40 sheep for 7 1/2 months. If one day, 3 horses eat as much as 5 cows and 6 cows as much as 10 sheep, what part of the rent should A pay?