Answer :
Given
A woman invested part of $22,000 at 5% interest and the rest at 8%.
And, her annual interest is $1,400.
To find how much did she invest at 5%.
Explanation:
It is given that,
The principal amount is $22,000.
Let x and y be the parts of $22,000 at 5% and 8%.
Therefore,
[tex]\begin{gathered} x+y=22000 \\ y=22000-x\text{ \_\_\_\_\_\_\lparen1\rparen} \end{gathered}[/tex]Since the total annual interest is $1400.
Then,
[tex]\begin{gathered} 1400=5\%\times x+8\%\times y \\ 1400=\frac{5}{100}\times x+\frac{8}{100}\times(22000-x) \\ 1400\times100=5x+8\times22000-8x \\ 140000=-3x+176000 \\ 3x=176000-140000 \\ 3x=36000 \\ x=\frac{36000}{3} \\ x=12000 \end{gathered}[/tex]Hence, she invested $12000 at 5%.