# Multile choice question #2

• February 10th 2011, 10:42 PM
Multile choice question #2
Q29: There are four prime no written in ascending order. The product of the
first three is 385 and that of the last three is 1001.The last no is?
A. 11
B. 13
C. 17
D. 19
how?
• February 10th 2011, 11:29 PM
Prove It
This one you would just use trial and error.

Write down the prime numbers up to $\displaystyle 19$ and work out the products of the four consecutive primes ending in $\displaystyle 11,13,17,19$.
• February 11th 2011, 03:31 AM
HallsofIvy
Why do you assume consecutive primes?
• February 11th 2011, 03:40 AM
Prove It
Quote:

Originally Posted by HallsofIvy
Why do you assume consecutive primes?

Because I stupidly read "ascending order" as "consecutive"...
• February 11th 2011, 05:36 AM
DrSteve
I think that in this question you can just write down the prime factorizations of the 2 given numbers, and the answer will magically appear.