Math
posted by Joel .
melissa invested a some of money at 3% annual simple inter she invested 3 times that some at 5 % annual simple interest
if her total yearly interest from both investments was 7200 how much was invested at 3% ?

Invested $X @ 3%.
Invested $3X @ 5%.
0.03X + 0.05*3X = 7200.
0.03X + 0.15X = 7200,
0.18X = 7200.
X = $40,000.
Respond to this Question
Similar Questions

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 … 
Math
Help! Toshiro Hashimoto invested some money at 4.5% simple interest and $1000 more than four times the amount at 6%. His total annual income for one year from interest on the two investments was $801. How much did he invest at each … 
Algebra
I invested $42,000 in three funds paying 5%, 7%, and 9% simple interest. The total annual interest from these investments was $2,600. The amount of money invested at 5% was $200 less than the amount invested at 7% and 9% combined. … 
math
Two investments earn a total annual income of $2825. One investment is in a 6.75% annual simple interest certificate of deposit. The other is in a 7.25% tax free annual simple interest account. The total amount invested is 40,000. … 
algebra
A total of $12,000 is invested in two funds paying 9% and 11% simple interest. If the yearly interest is $1,180, how much of the $12,000 is invested at each rate? 
algebra
Larry Mitchel invested part of his $32,000 advance at 7% annual simple interest and the rest at 6% annual simple interest. If this total yearly interest from both accounts was $2,050, find the amount invested at each. The amount invested … 
Math
An investment of $3,000 is made at an annual simple interest of 5%. How much additional monery must be invested at an annual simple interest rate of 8% so that the total annual interest earned is 7.5 of te original amount that you … 
simple interest
A total of $12,000 is invested into two simple interest accounts. On one account the annual simple interest rate is 12%, while on the second account the annual interest rate is 18%. How much should be invested at 12% so that the interest … 
math
An investment of $3,000 is made at an annual simple interest of 5%. How much additional money must be invested at an annual simple interest rate of 8%, so that the total annual interest earned is 7.5 of the original amount that you … 
Algebra
A woman invested some money at 8% and some at 9% annual simple interest. The interest for 1 year on the combined investment of $10,000 was $860. How much was invested at each rate?