Total number of saplings = per person 10x+610x trees, i.e.10x trees, and the remaining 6 trees are added.

Total number of saplings = 12x-6 (same as above, 6 saplings are missing).

Both sides are equal: 10x+6= 12x-6.

Namely: 2x= 16

x=6

Answer: There are six people planting trees.