Answer:
The slope of line representing Luigi's numbers from 30 seconds to 60 seconds is

Explanation:
At 30 seconds, he collected 14 coins
At 60 seconds, he collected 55 coins
time difference, Δt = 60 - 30
⇒ Δt = 30 seconds
additional coins collected in this time, Δc = 55 - 14
⇒ Δc = 41 coins
Now, slope of the line = Δc/Δt =

∴ The slope of line representing Luigi's numbers from 30 seconds to 60 seconds is
coins/sec