John starts at an elevation of 400 feet.  He travels downward at a rate of 10 feet down per minute for 5 minutes.  What is his elevation now?
How many feet did John travel down? ** He traveled down 10*5=<<10*5=50>>50 feet.
What is John's elevation now? ** So he is at an elevation of 400-50=<<400-50=350>>350 feet.
#### 350