Question 164192
Let's call the part of money invested at 8% x.  Therefore, that amount of money will earn x*.08 interest.  The rest of the money will be invested at 10%.  The rest of the money is (5400-x), because it is whatever part of the 5400 was not invested at 8% (x).  Therefore, that money will earn .1(5400-x) interest.  Now we just need to equate these two expressions:
<br />
{{{.08x = .1(5400-x)}}} which we can expand to {{{.08x = 540 - .1x}}}.  Let's combine like terms to arrive at {{{.08x + .1x = .18x = 540}}}.  Finally, divide both sides to arrive at {{{x = 540/.18 = 3000}}}.  This means 3000 is invested at 8% interest and 5400-3000= 2400 is invested at 10% interest.
<br />
To check our answer, we see that 3000 * .08 = 240 and 2400*.1 = 240