It is known that a shark can travel at a speed of 15 m/s.how far can a shark go in 10 seconds?

Start with 15 m/s. There are 2 units and you need to cancel the seconds to get meters. 

10 seconds has seconds as a unit. This can be used to cancel the sec in the denominator of 15 m/s. This just a little tip I use when I'm unsure about what to do. 

15 m/s x 10 s = 150 meters 

Hope I helped :) 

1.) distance is always positive while displacement can be negative as well.

2.) distance cannot be 0 but displacement can be 0.

3.) distance is a scalar quantity while displacement is vector quantity.