Question

Two bank robbers flee at 60 mph. 26 minutes later, a police helicopter follows at 120mph. How long til they catch them?

I figured 39 minutes. I takes the police 13 minutes to get to the 26 mile mark. Then the robbers move 13 miles forward. then the police take 6.5 minutes to go that far.please help!

Answer 1

You are correct as far as you got.

By the time the police get started, the robbers are 13 miles ahead.

The police are going 60 mi/hr faster than the crooks. So, you can think of the problem as the same thing as

the robbers are standing still 13 miles ahead, and the police are going 60 mi/hr. How long does it take them to get there? Another 13 minutes is all!

If you are a mile ahead of me, and I'm going 1 mi/hr faster than you are, it doesn't really matter how fast the speeds are, just that I have to make up distance of 1 mile, going 1 mi/hr faster than you. It will take me an hour, no matter how fast we are going.