Answer:
the inequality is 500 - 25x >= 200
this insures that she will have at least 200 at the end of the summer.
subtract 200 from both sides of that inequality and add 25x to both sides of that inequality to get 500 - 200 >= 25x
simplify to get 300 >= 25x
divide both sides of that equation by 25 to get 300 / 25 >= x
simplify to get 12 >= x
12 >= x means x <= 12.
when x is smaller than or equal to 12, she will be guaranteed to have at least 200 in the account at the end of the summer.
when x = 12, what is left in the account is 500 - 25 * 12 = 200.
when x = 11, what is left in the account is 500 - 25 * 11 = 225.
when x = 13, what is left in the account is 500 - 25 * 13 = 175.
the maximum number of weeks he can withdraw money from her account is 12.