Christy invests $2400 in one account and $1900 in an account paying 1 % higher interest. At the end of one year she had earned $449 in interest. At what rates did she invest?

Question

I need help with this question. How do I turn this information into an equation so I can solve it? If you solve it can you show your steps as well

Answer 1

Let the lower interest rate be r then the other interest rate is r+0.01 (fractions rather than percentages).

So after one year the total interest is 2400r+1900(r+0.01)=449.

Now we can solve for r: (2400+1900)r+19=449, 4300r=430, r=430/4300=1/10=0.1 or 10%.

So the interest rates are 10% and 11%.