Question

How many numbers are there between 100 and 1000 such that every digit is either 2 or 9? A. 10 B. 3 C. 6 D. 8​

Answer 1

Answer:

8 numbers

Step-by-step explanation:

Clearly, the numbers between 100 and 1000 are 3-digits numbers.

So, we have to form 3-digit numbers by using 2 and 9.

Clearly, the repetition of digit is allowed.

Each one of the unit's ten's and hundred's places can be filled in 2 ways.

Hence, the required number of numbers =(2×2×2)=8.