#### Answer

The opening bid was 175.

#### Work Step by Step

Let X represent the amount of the opening bid.
Since X is the opening bid, three times the opening bid means 3 $\times$ X = 3X.
35 more than three times the opening bid means 3X + 35.
The set of wheels were sold for 560.
So, we set up the equation:
3X + 35 = 560
Subtract 35 from both sides
3X = 525
Divide both sides by 3
X = 175