Answer: 175 defective bulbs.
Explanation:
 1. Keeping on mind that the inspector examined 100 light bulbs and found 7 defective, you can calculate the number of defective bulbs that there would be in a lot of 2500 bulbs as following:
 - Let's call the number of defective bulbs that there would be in a lot of 2500 bulbs 
 .
.
 - Then, you have:
 

 - Solve for x:
 

 

 2. Then, there would be 175 defective bulbs in a lot of 2500 bulbs.