Question

how many nos between 500and 1000 have exactly one digit is 8

Answer 1

580 through 998. We can choose 8 for the 1st digit in 1 way. We can choose the second digit as any of the 9 non-eights. We can choose the third digit as any of the 9 non-eights. That's 1×9×9 or 81 ways We can choose 8 for the 2nd digit in 1 way. We can choose the 1st digit as any of the 4 non-eight digits 5,6,7 or 9. We can choose the 3rd digit as any of the 9 non-eights. That's 1×4×9 or 36 ways We can choose 8 for the 3rd digit in 1 way. We can choose the 1st digit as any of the 4 non-eight digits 5,6,7 or 9. We can choose the 2nd digit as any of the 9 non-eights. That's 1×4×9 or 36 ways Total = 81+36+36 = 153 ways.

Answer 2

this is Ur required result in attachment