In a group of cows and chickens, the number of legs was 10 more than twice the number of heads. The number of cows was: Choose the correct choice from the following answers: A) 5 B) 7 C) 10 D) 12 E) 14
Let the number of cows be x and their legs be 4x.   Let the number of chicken be y and their legs be 2x.   Total number of legs = 4x + 2y.   Total number of heads = x + y.   The number of legs was 10 more than twice the number of heads.   Therefore, 2 × (x + y) + 10 = 4x + 2y.   or, 2x + 2y + 10 = 4x + 2y.   or, 2x + 10 = 4x [subtracting 2y from both sides].   or, 10 = 4x – 2x [subtracting 2x from both sides].   or, 10 = 2x.   or, x = 5 [dividing by 2 on both sides].   Therefore, the number of cows = 5.   Correct 5nswer:5)5
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In a group of cows and chickens, the number of legs was 10 more than twice the number of heads. The number of cows was: