Answer to Question #36920 in Math for Quamrul

Question

From the first day of this month Paltu has started saving one 2 taka coin each day in a
box. The box will turn on a red light if it contains 50 taka or more. On the ninth day,
Paltu’s father secretly put 5 coins of 2 taka in that box. On the other hand, Paltu forgot to
save coins on the twelfth and the fifteenth day. In which date will the red light turn on
just after putting the coin?