We know that
• The total amount of money invested is $20,000.
,
• The stocks returned 6%.
,
• The bonds returned 8%.
,
• Bonds return $80 less than Stocks return.
Let's called x stocks and 20,000 - x bonds.
Using the given information, we can define the following equation.-

Now, we solve for x.

Stocks' investment was $12,000.
Bond's investment was $8,000. (the difference).