Kendra photographed the Dogs-n-Suds annual car wash. She photographed 20 dogs and owners in all. If there was a total of 64 legs, how many dogs and owners are there?
Assume that every owner has 2 legs, each dog has 4 legs. Let X be the total number of owners and Y be the total number of dogs. Then & X+ Y = 20 On the other hand the total number of legs is equal to 4 X + 2 Y = 64
We have to resolve this system of equations: X+ Y = 20 4 X + 2 Y = 64
From the first equation: & X=20-Y Substituting to the second one we get: 4(20-Y)+2Y = 64 80 – 4Y + 2Y = 64 2Y = 24 Y=12, Whence X=20-12=8