Question

How many numbers are there in all from 4000 to 4999 (both 4000 and 4999 included) having at least one of their digits repeated?



a. 356



b. 216



c. 496?

Answer 1

Answer:

496

Explanation:

there are 1000 numbers from 4000 to 4999 (both inclusive)

numbers without repeated= 1×9×8×7=504

numbers with at least one of their digits repeated=1000-504=496