Use the simple interest formula.
-Melissa invested a sum of money at 3% annual simple interest. She invested three times that sum at 5% annual simple interest. If her total yearly interest from both investments was $5400, how much was invested at 3%?
A) $30,000
B) $67,500
C) $22,500
D) $202,500

Question

Quizplus · Accepted Answer

Let the sum of money invested at 3% be x. Therefore, 3x is invested at 5%. The total interest is the sum of the interest from both investments: Interest = (x*3%)+(3x*5%) = 5400. Solving this equation gives x = $30,000.

Use the Simple Interest Formula