Question 25707
Let x = the amount invested at 9%
Since the total amount invested was $9000, the amount invested at 8%
can be expressed as (9000 - x)
the interest received from the 9% investment is
.09x
the interest received from the 8% investment is
.08(9000 - x)
If you add these two interest incomes together, you get the toal interest
that Walt made, so
.09x + .08(9000 - x) = 770
.09x + 720 - .08x = 770
.01x = 50
x = 5000
this is the amount invested at 9%
(9000 - 5000)= 4000 is the amount invested at 8%