The Jackson family raises dogs that like looking for patterns in math. In a recent litter, Lightning, one of the girl dogs , noticed that she had two more sisters than brothers. Puffles, one of the boy dogs, was disappointed because he had three times as many sisters as brothers. How many puppies were there in the litter?

Solution

There are several ways to approach this problem. You could use trial-and-error and/or use a diagram. I'm going to use algebra by first letting *x* represent the number of girl dogs and *y* represent the number of boy dogs. The facts can be translated into these two equations.

These can be simplified and solved to show that there are 6 girls and 3 boys or a total of 9 dogs. For students not yet having the algebra skills required, since the numbers are small, it's easy to experiment until all the facts work out correctly.

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