Question

There are four prime numbers written in ascending order of magnitude. The product of the first three is 385 and of the last three is 1001. Find the fourth number ?

Answer 1

Factorising 385 we get 385=5*7*11
Factorising 1001 we get 1001=7*11*13

Hence the 4 numbers are 5, 7 11, 13
The 4th number is 13.