How to solve math/science problem.?

Question

Here's the question:

A particle moves through a gas at a speed of 15km/second. How far will it move in 5.5 seconds?

Answer 1

Speed = Distance/time = 15km/1 second

You want to know distance

Distance = Speed x time

= 15 x 5.5

= 82.5 km

Answer 2

if it moves 15 km in one second then it moves 30 km in two seconds and 75 km in 5 seconds. also if it moves 15 km in one second then it moves 7.5 km in half a second (.5).

so in 5.5 seconds it will go 82.5 km (75 + 7.5)