Speed is how fast something covers distance. Velocity is speed PLUS direction. They're often used interchangeably in everyday talk, but in physics they're different.
Type a value, pick units
62.1372
1 km/h = 0.6214 mph
Speed
Rearranges to distance = speed × time, and time = distance ÷ speed.
Speed vs velocity
In everyday talk they're the same, but in physics speed is just how fast (a number), while velocity is speed *plus direction* (a vector). 50 km/h is a speed; 50 km/h *due north* is a velocity.
Try it
You drive 240 km in 3 hours. Average speed?
240 ÷ 3 = 80 km/h.
Your turn
At 60 km/h, how far do you travel in 90 minutes?
Speed
Try it
Drive 240 km in 3 hours. Average speed?
240 / 3 = 80 km/h.
Try it
60 km/h in m/s?
60 km/h = 60 × 1000 m / 3600 s = 16.67 m/s. (Roughly: divide km/h by 3.6.)