Question

A submarine changes its position by −7 meters every second. What is the change in the submarine's position after 300 seconds?

Answer 1

if you take -7*300 is should equal  -2100

Answer 2

The submarine goes down 7 meters per second, so multiply 7 by 300 to see how many meters it went down.  
7 * 300 = 2,100  
So the submarines position is -2,100 from the original position.