Question 477895
9000=total money
Money at 9%=x
Money at 8%=9000-x (because it's the rest)


increase interest=770. so 9000+770= 9770.

So set up the equation:
{{{1.09x+1.08(9000-x)=9770}}} Because x+ 9% of x and (9000-x) + 8% of that equals 9770.

Simplify
{{{1.09x+9720-1.08x=9770}}}

Simplify again
{{{.01x+9720=9770}}}

Subtract 9720 from both sides.
{{{.01x=50}}}

Divide each side by .01

{{{x=5000}}}

Therefore:

$5000 was invested at 9%, and $4000 was invested at 8%.