49 ?11= 4 (group) ... 5 (pieces)
49 beads can form 4 groups, and the other 5 groups. The fifth in each group is a blue bead. So the 49th bead is blue.
121÷11=1(group)
12 1 Beads can form 1 1 group. The last bead in each group is red. So 12 1 beads are red.