SOLUTION: frank is eight years older than his sister. In three year he will be twice as old as she is. how old are they now

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Question 450534: frank is eight years older than his sister. In three year he will be twice as old as she is. how old are they now
Answer by poliphob3.14(115) About Me  (Show Source):
You can put this solution on YOUR website!
Let the sister's age now x years, then Frank's age is now x+8 years. After 3 years their ages will be: Frank's age x+11 and his sister's age x+3.
Since after 3 years Frank's age is twice as old as she is, write the equation.
x%2B11=2%28x%2B3%29=>x=5. Frank is now 5+8=13 years old.
Answer:Frank is now 13 years old and his sister is 5 years old.