How many numbers are there between 500 and 1000 which have exactly one of their digits as 8? Select one:
a. 180
b. 198
c. 648
d. 153?
Answers
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
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.
Hence ans is 153
HOPE IT HELPS ^_^
MARK IT AS THE BRAINLIEST