Let x be the number of cow.
Number of hens=180-x.
Since cows have 4 legs and hens 2,
So, 4x+2(180-x)=420.
or, 4x+360–2x=420
or, 2x=420–360
or, 2x=60
or,x=30.
So, number of cows is 30.
Step-by-step explanation:
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