Suppose each person plants N trees, then the total number of trees planted
Nx54 = 216.
Divide both sides of this equation by 54 gives:
N = 216/54 = 4.
Suppose they plant 1 tree each, then the total is 54 trees, but this is less
than the 216 we are told were planted.
So now guess they plant 2, then the total planted is 108, still not enogh.
Try 3, total is now 162 getting closser.
Try 4, total is now 216, which is the required total.
The round the numbers, then the total number of trees is 200, and planters
is 50. 50 planters would have to plant 4 trees each to plant a total of 200.
Now check that if 54 planters plant 4 trees each then the total is 216.