Question 1011698: ) Kristen is four times as old as Claire. Emily is six years older than Claire and 6 years younger than Sam. Anna is twice as old as Claire. If the sum of their ages is 81, how old is each person?
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617)   (Show Source):
You can put this solution on YOUR website! k,c,e,s,a, variables for those people.
Look for any clever substitutions and processes using them that you can find. More than one way. Something which appears a good start is substitute for e in all the equations, and simplify that resulting system.
Answer by MathTherapy(10551)  (Show Source):
You can put this solution on YOUR website! ) Kristen is four times as old as Claire. Emily is six years older than Claire and 6 years younger than Sam. Anna is twice as old as Claire. If the sum of their ages is 81, how old is each person?
Let Claire’s age be C
Then Kristen’s is: 4C
Emily’s is: C + 6
Sam’s is: C + 6 + 6, or C + 12 (Sam is 6 years older than Emily)
Anna’s is: 2C
We then get: C + 4C + C + 6 + C + 12 + 2C = 81
9C + 18 = 81
9C = 81 – 18
9C = 63
C, or Claire’s is:  , or 
You should be able to substitute C to find all other ages.
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