Answer:
the Jack speed is greater than the Nas speed 
 v₁ = 2.08 m / s > v2 = 1.85 m / s
Step-by-step explanation:
 For this exercise we can find the average speed of each of the boys, the average speed is defined as the displacement in the time interval 
 v = x / t 
 
 Jack. 
It tells us that it travels x = 15 km in a time of t = 2 h 
let's reduce the magnitudes to the SI system 
 x = 15 km (1000 m / 1 km) = 15 10³ m 
 t = 2 h (3600 s / 1 h) = 7200 s 
 
let's calculate 
 v₁ = 15 10³/7200 
 v₁ = 2.08 m / s 
 
Nas travels a distance of x = 10 km in a time of t = 1.5 h 
 x = 10 km = 10 10³ m 
 t = 1.5 h (3600s / 1h) = 5400 s 
let's calculate the speed 
 v2 = 10 10³/5400 
 v2 = 1.85 m / s 
 
From these results we can see that the Jack speed is greater than the Nas speed