She beat me to it, but she didn't bother to explain how to
get the answer.
What is a number that is a multiple of 2 and 7, is less than
100 but greater than 50 and the product of three different
prime numbers?
2 and 7 are primes, so those have to be two of the primes
of which the required number is the product of, so we need
another prime p so that our number is 2*7*p
50 < 2*7*p < 100
50 < 14p < 100
Divide through by 14
3.57... < p < 7.14...
The only prime different from 2 and 7
between those two values is 5.
So p = 5
The number is therefore 2*7*p = 2*7*5 = 70.
Edwin
