Question

वर्ग अंतराल 15 से 20 तक मध्य बिंदु​

Answer 1

Explanation:

Find the number of integers between 1000 and 4000 which can be formed by using the digits 1 ,

2, 3 and 4

a) if the digits can be used only once.

b) if each digits may be used more than once.