Owen's grandmother put some money into his savings account on the day he was born. Today, Owen turns 18 years old, and he's discovered that he has earned $225 in simple interest on his grandmother's money. If the yearly interest rate was 5%,
how much money did his grandmother deposit at the time of his birth?

answer: 590

step-by-step explanation:

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15