Question 1174009
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Hi,
A farmhouse shelters 10 animals. Some are pigs some are ducks,
 Altogether there are 36 legs. How many of each animal are there?
 Let x be the number of pigs and (10-x) be the number of ducks.
  4x + 2(10-x) = 36 legs
  4x + 20 - 2x = 36
       2x = 16
        x =  8, the number of pigs,  2 is the number of ducks {{{10-8 }}} 
Checking our Answer:
 4*8 + 2*2 = 36  checks.      
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