Mr chan bought some pencils for a group of students. if he gives them 2 pencils each, he will have 10 pencils left. if he gives them 3 pencils each, he will have none left. how many students are in the group?

In the figure below, ∠dec ≅ ∠dce, ∠b ≅ ∠f, and segment df is congruent to segment bd. point c is the point of intersection between segment ag and segment bd, while point e is the point of intersection between segment ag and segment df. the figure shows a polygon comprised of three triangles, abc, dec, and gfe. prove δabc ≅ δgfe.