<PRE><B>Question 438267</B>
 A boy is 17 years old and his sister is twice as old. When the boy is 23 what will be the age of his sister. 
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Equations:
b = 17; s = 2*17 = 34
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The boy will be 23 in 6 years.
In 6 years his sister will be 34+6 = 40.
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Cheers,
Stan H.</PRE>