Question

Mikael runs with a speed of 3 m/s for 45 seconds. How far does Mikael run?

Answer 1

135m in 45 seconds.  Multiply 3 and 45. 

Answer 2

Speed of 3 m per second means that in one second he ran 3 m, so every second he runs another 3 m.
1 sec. 3m
2 sec. 3+3 or 3•2= 6m
.
45 sec 3•45= 135m