The number of prime factors in the expression $6^{10} \cdot 7^{17} \cdot 11^{27}$ is equal to
Aptitude
Number System
Difficulty: Easy
Choose an option
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A54
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B64
-
C71
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D81
Answer
Correct Answer: 64
Explanation
### Concept & Strategy
To find the total number of prime factors in a product of exponents, you must first prime factorize every base. Once all bases are prime, the total number of prime factors is simply the sum of all the exponents.
### Step-by-Step Solution
* **Given:**
* The mathematical expression: $6^{10} \cdot 7^{17} \cdot 11^{27}$
* **Calculation / Deduction:**
1. Inspect the bases: $6$, $7$, and $11$.
2. Base $7$ and base $11$ are already prime numbers.
3. Base $6$ is a composite number. Prime factorize it:
$$6 = 2 \times 3$$
4. Substitute this back into the expression using exponent rules $(a \cdot b)^n = a^n \cdot b^n$:
$$6^{10} = (2 \times 3)^{10} = 2^{10} \cdot 3^{10}$$
5. Rewrite the full expression with only prime bases:
$$2^{10} \cdot 3^{10} \cdot 7^{17} \cdot 11^{27}$$
6. The exponents represent how many times each prime factor appears. Add the exponents to find the total count:
$$Total Prime Factors = 10 + 10 + 17 + 27 = 64$$
### Exam Strategy & Shortcut
Scan the bases. $7$ and $11$ are prime, contributing $17$ and $27$ directly. $6$ breaks into two primes ($2$ and $3$). Thus, the power of $10$ applies twice ($2 \times 10 = 20$). Add them up: $20 + 17 + 27 = 64$. You can do this entirely mentally.
### Common Pitfall
The most frequent error is ignoring the base $6$ and simply adding the given exponents: $10 + 17 + 27 = 54$. Always ensure every single base is reduced to prime numbers before summing powers.
### Final Answer
Therefore, the correct answer is 64.