A two-digit positive integer has the property that when 109 is divided by , the remainder is 4. What is the sum of all such two-digit positive integers ?
Solution
Suppose that the quotient of the division of 109 by is . Since the remainder is 4, this is equivalent to or . Put another way, must be a positive integer divisor of 105. Since , its positive integer divisors are . Of these, 15,21 and 35 are two-digit positive integers so are the possible values of . The sum of these values is .
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