Question 229212
Amy invests a part of $12000 in bonds paying 11% interest.
 The remainder is in a savings account at 8%. 
If she receives $1200 in interest for 1 year, how much does she have invested at
 each rate? 
:
let x = amt invested at 11%
"The remainder is in a savings account at 8%." therefore:
(12000 - x) = amt invested 8%
:
Total interest from the two investments = $1200
.11x + .08(12000-x) = 1200
:
Multiply what's inside the brackets
.11x + 960 - .08x = 1200
.11x - .08x = 1200 - 960
.03x = 240
x = {{{240/.03}}}
x = $8000 invested at 11%
then
12000 - 8000 = $4000 invested at 8%
;
:
Prove this to yourself, find the total interest
.11(8000) + .08(4000)
880 + 320 = 1200