Bill thought he bought 70 chihuahuas, but some of them turned out to be rats. If the number of rats was 6 times the number of chihuahuas, how many rats did he buy?
Let's be accurate as possible. Think before you answer.
60
Let r be the number of rats and c be the number of real chihuahuas.

We know that r + c = 70 and r = 6c.

Substituting the second equation into the first equation, we get 6c + c = 70.

Combining like terms, we get 7c = 70.

Dividing both sides by 7, we get c = 10.

Substituting this back into r = 6c, we get r = 10 * 6 = 60.

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Final answer: 60