Posted by Briana on .
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%?

algebra 
Reiny,
part at 12%  x
part at 10%  7500x
solve for x ....
.12x + .10(7500x) = 890