Math, asked by mamt5apisarikt, 1 year ago

How many numbers are there between 99 and 1000 having at least one of their digits 7

Answers

Answered by kvnmurty
3
99   ......   1000

Numbers with at least one digit = 7 ?

107, 117, 127 ... 167, 170, 171, .. 179, 187, 197..
               :
907 , 917, 927, ...  967, 970, 971, ...979, 987, 997

So there are 10 + 9 for each century.

Hence there are :   9 * 19 = 171

kvnmurty: clik on thanks. select best ans
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