question_answer

The number of natural numbers less than 7,000 which can be formed by using the digits 0, 1, 3, 7, 9 (repetition of digits allowed) is equal to: [JEE Main Online Paper (Held On 09-Jan-2019 Evening]

A) 372                              

B)               375  

C)               250                              

D)               374

Correct Answer: D

Solution :

There are 3 ways to fill I position (0, 1, 3) for remaining digits there are 5 ways hence ans \[=\text{ }3.\text{ }5.\text{ }5.\text{ }5-1\text{ }(0000\] not included) \[=375-1=374\]