Answer:
Mr. Martin drove 415 miles this week.
Explanation:
The question says Mr. Martin drove 125 miles more than last week. How many miles did Mr. Martin drive this week?
How many miles did he drive last week?
Remember: 290 miles is the miles he drove last week.
The problem says he drove 125 miles AND 290 miles this week. So you take the SUM of them to see how many miles he drove together.
290 + 125 = 415