Potential energy Ex8-C Q:11

A ball of mass 0.02 kg is projected vertically upwards through oil. The ball has initial speed (35/12) m/s. The oil exerts a resistance of 0.1 t^0.5 ( square root of t divided by10)N, where "t" s is the time from when the ball was projected.
Work out the increase in the potential energy of the ball from the start to when the ball was projected.

My answer to this question is 0.02x10x1.600946..= 0.3201J. but book answer is 0.075 J.
Please anybody clarify it ?

here is working as well as the question.