Hi there, Rukie! This problem can be solved by divided the number given by one of the ratios, and multiplying that answer by the other ratio. Since Bob invested the greater amount, we can divide his investment ($450) by 8, getting the answer of 56.25 (that's the unit of the ratio). We can then multiply that number by 7 to calculate Ellen's investment, which comes out to be $393 dollar and 75 cents. Hope that helps!
