Question

Ken has $950 in a savings account at the beginning of the summer. He wants to have at least $600 in the account by the end of the summer. He withdraws $35 a week for food, clothes and movie tickets. Write an inequality for the number of weeks Ken can withdraw money, and describe the solution.

Answer 1

Every week he withdraws $35 from the $950 in his savings, and he wants at least $600 by the end of the summer. So we could write:

$\sf 950-35x\ge 600$

Where 'x' is the number of weeks. Now let's solve it for 'x'.

Subtract 950 to both sides:

$\sf -35x\ge -350$

Divide -35 to both sides, don't forget to switch the sign when dividing/multiplying by a negative number:

$\sf x\le 10$

So he can only withdraw at money for at most 10 weeks if he wants at least $600 left in his account.