document.write( "Question 1210186: Find the number of positive integers that are divisors of at least one of 6^{6}, 10^{10}, 15^{15}, and 30^{30}.
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Algebra.Com's Answer #851508 by CPhill(1959)![]() ![]() You can put this solution on YOUR website! Let's break down this problem step by step.\r \n" ); document.write( "\n" ); document.write( "**1. Prime Factorization**\r \n" ); document.write( "\n" ); document.write( "* $6^6 = (2 \cdot 3)^6 = 2^6 \cdot 3^6$ \n" ); document.write( "* $10^{10} = (2 \cdot 5)^{10} = 2^{10} \cdot 5^{10}$ \n" ); document.write( "* $15^{15} = (3 \cdot 5)^{15} = 3^{15} \cdot 5^{15}$ \n" ); document.write( "* $30^{30} = (2 \cdot 3 \cdot 5)^{30} = 2^{30} \cdot 3^{30} \cdot 5^{30}$\r \n" ); document.write( "\n" ); document.write( "**2. Understanding Divisors**\r \n" ); document.write( "\n" ); document.write( "A divisor of any of these numbers will be of the form $2^a \cdot 3^b \cdot 5^c$, where:\r \n" ); document.write( "\n" ); document.write( "* $0 \le a \le 30$ (since $2^{30}$ is the highest power of 2) \n" ); document.write( "* $0 \le b \le 30$ (since $3^{30}$ is the highest power of 3) \n" ); document.write( "* $0 \le c \le 30$ (since $5^{30}$ is the highest power of 5)\r \n" ); document.write( "\n" ); document.write( "**3. Total Possible Divisors**\r \n" ); document.write( "\n" ); document.write( "If we consider all possible combinations of a, b, and c, we have:\r \n" ); document.write( "\n" ); document.write( "* 31 choices for a (0 to 30) \n" ); document.write( "* 31 choices for b (0 to 30) \n" ); document.write( "* 31 choices for c (0 to 30)\r \n" ); document.write( "\n" ); document.write( "Therefore, the total number of possible divisors is $31 \cdot 31 \cdot 31 = 31^3 = 29791$.\r \n" ); document.write( "\n" ); document.write( "**4. Inclusion-Exclusion Principle**\r \n" ); document.write( "\n" ); document.write( "We need to find the number of divisors that are divisors of *at least one* of the given numbers. We can use the inclusion-exclusion principle.\r \n" ); document.write( "\n" ); document.write( "* Let A be the set of divisors of $6^6$. \n" ); document.write( "* Let B be the set of divisors of $10^{10}$. \n" ); document.write( "* Let C be the set of divisors of $15^{15}$. \n" ); document.write( "* Let D be the set of divisors of $30^{30}$.\r \n" ); document.write( "\n" ); document.write( "We want to find $|A \cup B \cup C \cup D|$.\r \n" ); document.write( "\n" ); document.write( "Since $30^{30}$ contains all prime factors of the other 3, any divisor of $6^6$, $10^{10}$, or $15^{15}$ will also be a divisor of $30^{30}$. \n" ); document.write( "Therefore, $|A \cup B \cup C \cup D| = |D|$.\r \n" ); document.write( "\n" ); document.write( "* $|D| = (30+1)(30+1)(30+1) = 31^3 = 29791$\r \n" ); document.write( "\n" ); document.write( "**5. Final Answer**\r \n" ); document.write( "\n" ); document.write( "The number of positive integers that are divisors of at least one of the given numbers is $31^3 = 29791$.\r \n" ); document.write( "\n" ); document.write( "**Therefore, the answer is 29791.** \n" ); document.write( " \n" ); document.write( " |