SOLUTION: 31 heads and 104 feet, how many dogs and how many birds

Question 985556: 31 heads and 104 feet, how many dogs and how many birds
Found 2 solutions by solver91311, macston:
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

is dogs and is birds.

Solve for and

Of course, this assumes that there are no three-legged dogs in the group.

John

My calculator said it, I believe it, that settles it

Answer by macston(5194) (Show Source): You can put this solution on YOUR website!
.
D=number of dogs; B=number of birds
D+B=31
D=31-B
.
4D+2B=104 Substitute for D.
4(31-B)+2B=104
124-4B+2B=104
-2B=-20
B=10 ANSWER 1: There were 10 birds.
D=31-B=31-10=21 ANSWER 2: There were 21 dogs.
.
CHECK:
4D+2B=104
4(21)+2(10)=104
84+20=104
104=104

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