Answer:
The most to be invested in Bond X (pays 6.75%) is $18,000
Step-by-step explanation:
Hi, first, we have to set 2 equations. Let "X" be the bond that returns 6.75% and "Y" the bond that returns 7.25%.

We also know that from both investments, the investors want $3,245, therefore:

Now, we substitute Y for 46,000-X
and this is what we get.




So, the most that can be invested in the 6.75% bond is $18,000
Best of luck.