Compute TR=P×Q at each row, note AR always equals P, and find MR as the change in TR between rows; then compare the falling AR-MR gap here to the flat, equal AR=MR of Exercise 2.

$TR=P\times Q$ at each output:

$AR=TR/Q$, which will always simply equal the given price:

$MR=\Delta TR/\Delta Q$ (successive TR differences, with $TR_0=0$):

Completed schedule:

Students sometimes compute MR incorrectly as simply the price of the NEXT unit alone (e.g., taking MR at Q=2 to be Rs. 18, the price) — but MR must account for the revenue lost on ALL earlier units too, since they must now also be sold …