When the decrease in velocity (the acceleration) is uniform, the average velocity is [Initial velocity - Final velocity]/2
We know tha the initial velocity is 0.96 rev / sec and the final velocity is 0,
Then, the average velocity is [0.96 / 2 ]rev /sec = 0.48 rev/sec.
Also, by defintion,
average velocity = number of rev / time,
From which, number of rev = average velocity * time
So, number of rev = 0.48 rev/sec * 2.4 min * 60sec /min = 69.12 rev
Answer: 69.12 revolutions
