How many three digit numbers can be formed in which if one digit is 3 then it must be follwed by 7 and repetetion of digits is not allowed Choose the correct answer:
A) 12  B) 13  C) 14  D) 15  E) 16
if 7 is to be followed by 3 , then the numbers will be either 37_ or _37.   for 37_ ,we have 370,371,372,374,375,376,378,379.   and for _37,we have 137,237,437,537,637,837,937.   therefore i think the answer is 15   ANSWER:15
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How many three digit numbers can be formed in which if one digit is 3 then it must be follwed by 7 and repetetion of digits is not allowed