# Math

posted by .

A woman invested \$15,000, part at 7% annual interest and the rest at 8%. If she earned \$1,100 in income over a one-year period, how much did she invest at 7%?

• Math -

Invested \$P @ 7%.
Invested \$(15,000-P) @ 8%.

P*r*t + (15000-P)*r*t = \$1100.
P*0.07*1 + (15000-P)*0.08*1 = 1100
0.07P + 1200 -0.08P = 1100
-0.01P = 1100-1200 = -100
P = \$10,000 @ 7%.

## Similar Questions

1. ### Math

An investment advisor invested a total of \$12,000, part at 2.5% annual simple interest and part at 4% annual simple interest. The amount of interest earned for 1 year was \$426. How much was invested at the 2.5% rate and how much was …
2. ### algebra

invest \$2,000, part earns 6% year and reh rest earned 11% year. Interest at end of year = \$155. How much is invested at each rate?
3. ### intermediate algebra

need the equation for this problem. Mike invested \$706 for one year. He invested part of it at 5% and the rest at 3% at the end of the year he earned \$28.00 in interest. How much did mike invest at each rate of interest
4. ### algebra

HELP! Please Calvin invested \$7500 for one year, part 12% annual interest and the rest at 10% annual interest. His total interest for the year was \$890. How much money did he invest at 12%?
5. ### algebra

Calvin invested \$7500 for one year, part 12% annual interest and the rest at 10% annual interest. His total interest for the year was \$890. How much money did he invest at 12%?
6. ### Pre Algerbra

I invested \$3,000, part at 2% and the rest at 5% simple interest. After 1 year, I earned a total of \$117 in interest. How much did I invest at each rate?