time given 80 s and 100 s
t f= 100 s v f= 20 m/s
t i= 80 s v i= 2 m/s [i think its 2 because its not touching the x-axis so,it cannot be 0]
use the equation now:
A= v f-v i /t f-t i
v f-v i = 20-2 =18 [if u use vi as 0 then its 20 ][ then the answer is 1]
t f-t i = 100-80 =20
answer is 18/20