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?
Let the number of years after which Agnes will be twice as old as Jane be x
After x years, 25+x = 2(6+x)
Solving the equation by expanding and collecting like terms gives: x-2x = 12-25
Further solving gives: -x = -13
Multiplying both sides by -1 gives x = 13
#### 13