Agnes is 25 years old and her daughter, Jane is 6 years old. In how many years will Agnes be twice as old as Jane?
Define a variable ** Let the number of years after which Agnes will be twice as old as Jane be x
How old will Agnes be after x years? ** After x years, 25+x = 2(6+x)
Simplify ** Solving the equation by expanding and collecting like terms gives: x-2x = 12-25
Simplify ** Further solving gives: -x = -13
Simplify ** Multiplying both sides by -1 gives x = 13
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