Question

How many numbers are there between 300 and 400 in which 7 occurs only once?

Answer 1

307,317,327,337,347,357,367,370,371,372,373,374,375,376,378,379,387 and 397.

There are 18 numbers between 300 and 400 in which 7 occurs only once.

Answer 2

hye
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we have to find  How many numbers are there between 300 and 400 in which 7 occurs only once

so the numbers are
307,317,327,337,347,357,367,370,371,372,373,374,375,376,378,379,387,397

=>  18 numbers

so there are 18 numbers  between 300 and 400 in which 7 occurs only once
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hope it helps