Make sure that you read the question carefully several times.
We are looking for how much she invested in EACH account.
*x* = amount invested in 7%
Since the two accounts together need to be $20000, then we can take
the total (20000) and subtract from it the "given" number in the 7% account
(*x*):
**20,000 - ***x* = amount invested in 9%
Note that you could have reverse those, the problem would still work
out the same. |