#### Answer

Out of 510 florescent bulbs, 18 would be defective.

#### Work Step by Step

Given:
Out of 85 florescent bulbs, 3 were found defective.
Thus, if there were 510 florescent bulbs, then $\frac{510 \times 3}{85}$ would be defective..... (Cross multiplying $\frac{3}{85}$ = $\frac{x}{510}$ , where x is number of damaged bulbs.)
$\frac{510 \times 3}{85}$ = $\frac{85 \times 6 \times 3}{85}$ = 6 $\times$ 3 = 18.
Thus out of 510 florescent bulbs, 18 would be defective.