Math CentralQuandaries & Queries


Question from Cole, a student:

Susan and Russell are brother and sister. Susan says that in two years she will be twice Russell's current age. Russell says that he's only three years younger than Susan. How old is each of the siblings?

Hi Cole,

I'll help get you started.

Suppose Susan's current age is $s$ years and Russell's current age is $r$ years. How old will Susan be in 2 years? The problem states that this is twice Russell's current age. This gives you an equation containing the variables $r$ and $s.$

Russell says he is 3 years younger than Susan. This gives you a second equation in $r$ and $s.$ Solve the two equations for $r$ and $s$ and verify your answer.

If you need more assistance write back and tell me what you have done and I will try to help,

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