SOLUTION: Lon Triah invested $5000 at a local bank. Part was invested at 6% simple interest and the remainder at 10% simple interest. At the end of one year, Lon had earned $428 interest. Ho
Question 1180729: Lon Triah invested $5000 at a local bank. Part was invested at 6% simple interest and the remainder at 10% simple interest. At the end of one year, Lon had earned $428 interest. How much was invested at each rate? Answer by ikleyn(52801) (Show Source):
x invested at 6%.
(5000-x) invested at 10%.
The total interest equation
0.06x + 0.1(5000-x) = 428
From the equation
x = = 1800.
ANSWER. $1800 invested at 6% and the rest, (5000-1800) = 3200 dollars, invested at 10%.
CHECK. 0.06*1800 + 0.1*3200 = 428 dollars, total interest. ! Correct !
Solved.
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It is a standard and typical problem on investments.
You will find there different approaches (using one equation or a system of two equations in two unknowns), as well as
different methods of solution to the equations (Substitution, Elimination).
