Question 1142477
x = amount invested in 3% account.
y = amount invested in 4$ account.


x + y = 15000
.04 * x + .03 * y = 520


solve for y in the first equation to get y = 15000 - x.


replace y with 15000 - x in the second equation to get:


.04 * x + .03 * (15000 - x) = 520.


simplify to get .04 * x + .03 * 15000 - .03 * x = 520.


simplify further and combine like terms to get .01 * x + 450 = 520.


subtract 450 from both sides of the equation to get .01 * x = 70.


solve for x to get x = 70 / .01 = 7000.


that makes y = 15000 - 7000 = 8000.


confirm by replacing x with 7000 and y with 8000 to get .04 * 7000 + .03 * 8000 = 520, which becomes 280 + 240 = 520, confirming the solution is correct.


your solution is that she invested 7000 at 4% and 8000 at 3%.