The Monkey King ate half of Pig's food, and Friar Sand ate a third of Pig's food.

We can know that the watermelon eaten by Pig Bajie: the Monkey King: Friar Sand =6:3:2.

The watermelon eaten by Friar Sand is 2n, so the watermelon eaten by Pig Bajie is 6n, and the watermelon eaten by the Monkey King is 3n.

So there are (2n+3n+6n)+1=11n+1watermelon in this watermelon field. (n is a positive integer)

When n= 1, 6n = 6,11n+1=12.

I wish you progress in your studies and go up a storey still higher! (*^__^*)