Answer
a) If N objects are placed into k boxes, then there is at least one box containing at least [$\frac{N}{k}$].
b) There are at least 10 integers ending with the same digit.
Work Step by Step
a) If N objects are placed into k boxes, then there is at least one box containing at least [$\frac{N}{k}$].
b) According to the generalized pigeonhole principle, at least one box must contain [$\frac{91}{10}$]=10. .There are at least 10 integers ending with the same digit.
