Answer:
The amount invested at 4% is $20,500 and the amount invested at 10% is $500
Step-by-step explanation:
Let
x -----> the amount invested at 4%
(21,000 -x) ----> the amount invested at 10%
we know that
The interest of the amount invested at 4% plus the interest of the amount invested at 10% must be equal to $870
so
Solve for x
therefore
The amount invested at 4% is $20,500 and the amount invested at 10% is $500