Question

How many numbers from 0 to 10 , 000 have exactly one digit equal to 5 ?

Answer 1

Answer:

2916

Step-by-step explanation:

There are 4 places to put the 5. There are 9 choices (0-4 and 6-9) for remaining 3 digits, so they can be chosen in 9^3 = 729 ways.  

The total is 4 * 729 = 2916

Answer 2

Answer: 2916

Step-by-step explanation:

As per the question we have to find how many numbers from 0 to 10,000 numbers have exactly one digit equal to 5

Then as we know Number 10,000 does not have any digit equal to 5.

the remaining numbers from 0 to 9,999 have 4 digits (which includes 0 from left side)

1-digit numbers, 5 in the unit place and numbers formed is 1

2-digit numbers, 5 in the units place and 8 other Non-Zero digits in the tens place and we have to add plus 5 in the tens place and 9 other digits in the units place,

8 * 1 + 1 * 9 = 17

Similarly, for 3-digit numbers: 5 in the units place, or 5 in the tens place, or 5 in the hundreds place: Numbers formed

8*9*1+8*1*9+1*9*9 =72+72+81 =225

and similarly for 4 digit numbers 5 in the units place or

5 in the tens place , or

5 in the hundreds place or

5 in the thousands place then number formed

8 * 9 * 9 * 1 + 8 * 9 * 1 * 9 + 8 * 1 * 9 * 9 + 1 * 9 * 9 * 9 = 648 + 648 + 648 + 729 = 2673.

then therefore total numbers in the range of 0 to 10,000 having only 5 is

1+17+225+2673 = 2916