Question

All prime numbers less than 10 are the only prime factors of this number. Find the number given that none of the factors repeat themselves.

• A. 1890
• B. 17
• C. 200
• D. 210

Answer 1

The correct option is D

210

Let the number be $n$.
Let us now list all the prime numbers that are less than 10:
2,3,5 and 7.
Now, since it is given that none of the factors repeat themselves, we can conclude $n$ to be the product of these four numbers.
i.e.,$n=2\times 3\times 5\times 7=210$
Thus, the required number is 210.