What is the tens digit of the smallest six-digit positive integer that is divisible by each of , and 15?
Solution
Among the list , the integers 11 and 13 are prime. Also, and and and . For an integer to be divisible by each of these six integers, must include at least two factors of 2 and one factor each of . Note that . (This is the least common multiple of .) To find the smallest six-digit positive integer that is divisible by each of , we can find the smallest six-digit positive integer that is a multiple of 60060. Note that and that . Therefore, the smallest six-digit positive integer that is divisible by each of is 120120. The tens digit of this number is 2.
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