Posted by lori on Friday, September 6, 2013 at 11:18pm.
A professor wants to supplement her pension with investment interest. If she invests $26,000 at 7% interest, how much more would she have to invest at 9% to achieve a goal of $4,160 per year in supplemental income?

math  Graham, Friday, September 6, 2013 at 11:35pm
What is the interest period? Annually, quarterly, monthly, or what?
Assuming annually. Make adjustments if otherwise.
Supplemental income is interest earned over the period. For one year this is:
4160 = 0.07*26000 + 0.09*x
Solve for x.