human
The sum of Cooper’s, Dante’s, and Maria’s ages is 31. Dante is twice as old as Cooper. Maria is one year older than Dante. How old is Cooper?
assistant
Define a variable ** Let X be the age of Cooper. So Dante is X*2 years old and Maria is X*2 + 1 year old.
Write an equation ** The sum of Cooper’s, Dante’s, and Maria’s ages is X + (X*2) + (X*2 + 1) = 31.
Combine like terms ** Combining like terms, we get X*5 + 1 = 31.
Subtract 1 ** Subtracting one from both sides, we get X*5 = 30.
Divide by 5 ** Dividing both sides by 5, we get X = 6 years old.
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