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Question 965175: George and Linda each have 20 dollars in the bank. Each week George adds 3 dollars to his account. Linda adds 1 dollar to her account each week. After how many weeks does George have twice as much as Linda?1
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! looks like 20 weeks.
in 20 weeks, george will have 20 + 3 * 20 = 20 + 60 = 80
in 20 weeks, linda will have 20 + 1 * 20 = 20 + 20 = 40
80 is 2 times 40.
the formula for george is y = 20 + 3x
the formula for linda is y = 20 + x
x represents the number of weeks.
when george has 2 times as much as linda, then 20 + 3x is equal to 2 * (20 + x)
solve that equation for your answer.
20 + 3x = 2 * (20 + x) becomes:
20 + 3x = 40 + 2x.
subtract 2x from both sides of the equation and subtract 20 from both sides of the equation to get:
3x - 2x = 40 - 20
simplify to get x = 20
that's your solution.
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