There are several information's of immense importance that are already given in the question. Based on those information's the answer to the question can be very easily determined.
Initial velocity of the object (V1) = 65 m/s
Final velocity of the object (V2) = 98 m/s
Time taken by the object = 12 seconds
Then
Acceleration of the object = (V2 - V1)/Time taken
= (98 - 65)/12 m/s^2
= 33/12 m/s^2
= 2 9/12 m/s^2
= 2.75 m/s^2
So the acceleration of the object can be written as 2 9/12 meter per square second or 2.75 meter per square second.
