To find the percentage invested in bonds, we need to add the amounts invested in U.S. Treasuries and high-grade corporate bonds, and then divide by the total value of the portfolio:
Total amount invested in bonds = $45,000 + $32,000 = $77,000
Total portfolio value = $45,000 + $32,000 + $74,000 = $151,000
Percentage invested in bonds = (Total amount invested in bonds / Total portfolio value) x 100%
= ($77,000 / $151,000) x 100%
= 51.0%
Therefore, the answer is 51%.
I hope this helps you!