Question

Natalie and her sister opened a savings account at the same time. Natalie deposited $100 and will deposit $10 each month. Her sister deposited $25 and will deposit $25 each month. When will Natalie have less money in her account that her sister?

Answer 1

6 months

Explanation:

We can think of Natalie as 100 + 10x and her sister as 25 + 25x. If we put them together, we will get 100 + 10x < 25 + 25x, We can simplify it by moving the 25 to the left side and 10x to the right side. Then we will get 75 < 15x, and the smallest solution is 6 because 5 * 15 is equal to 75