A small plot is worked by four people. The owner, Girish, says put four more on the same plot and…

Why

Girish is applying a rule that does hold at first: going from too few workers to enough really can lift a harvest a lot. But the plot of land is fixed, and so are the tools. Add more and more people to the same land and each extra person has less ground to work, more waiting for a turn with the plough, more time simply standing idle; the tenth worker on a tiny plot adds almost nothing, and past a point they get in each other's way and output can even drop. This is why one small field cannot feed a village just by crowding more hands onto it. Picture ten people trying to cook on one small stove. Test: think through what the fifth, and then the fifteenth, extra worker on one small plot actually does all day. Latika is right: when one input grows while the others stay fixed, the extra gain from it keeps shrinking.