This is a question of consumer choice(preference and utilities) under micro economics. I am not understanding well the calculation of utilities.

The following table shows hypothetical figures for total utility derived from consumption of three goods, A, B and C by a farmer. The prices of A, Band C are Ksh. 5.00, Ksh. 3.00 and Ksh. 2.00 respectively. No. of units Total Utility Total Utility Total Utility Consumed TUA TUB Tuc 72 60 64 4 120 104 120 6 160 136 160 195 160 188 225 180 204 245 188 216 14 260 192 224 Determine the marginal utilities for each good b) Find the optimal quantities of each good for consumption Find the total expenditure at the optimal level of consumption What is the effect of a reduction in the price of A both in the short-run and the long-run equilibrium