SOLUTION: Sister is 10 yrs older thn brother , after 3 yrs sister is twice thn brother so what r the ages of both..........???

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Question 789602: Sister is 10 yrs older thn brother , after 3 yrs sister is twice thn brother so what r the ages of both..........???
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
b= age of the brother, in years, at the start of the 3 years
b%2B10= age of the sister, in years, at the start of the 3 years
b%2B3= age of the brother, in years, after 3 years
b%2B10%2B3=b%2B13= age of the sister, in years, after 3 years

If after 3 years the sister is twice as old as the brother,
b%2B13=2%28b%2B3%29
Then, solving step by step:
b%2B13=2%28b%2B3%29-->b%2B13=2b%2B2%2A3%29-->b%2B13=2b%2B6%29-->b%2B13-6=2b%29-->b%2B7=2b%29-->7=2b-b%29--> highlight%28b=7%29
That means:
b%2B10=7%2B10=highlight%2817%29= age of the sister, in years, at the start of the 3 years
b%2B3=7%2B3=10= age of the brother, in years, after 3 years
b%2B13=7%2B13=20= age of the sister, in years, after 3 years
At the start the brother is 7 years old, and the sister is 17.
After 3 years, the brother is 10, and the sister is 20.