Question

How many digits between 5000 and 7000 can be formed using the digits 3 to 8, when any digit can occur any number of times?​

Answer 1

The Numbers between 5000 and 7000 can be formed using the digits 3 to 8, when any digit can occur any number of times is 432.

Given all the numbers should lie between 5000 and 7000.

• Therefore , number at 1000's place have 2 possibilities ,can be 5 and 6 .

• Numbers at the 100s , 10s and units place can be between 3 and 8 .

• Since it can occur any number of times,
• 100s place can have 6 possibilities.
• 3 , 4, 5 ,6 , 7 and 8 .
• 10s place also have 6 possibilities and
• Units place can also have 6 possibilities.
• Therefore total numbers = 2 x 6 x 6 x 6 = 2 x 6³ = 432