clue 1. my number is a multiple of 2 and 7
clue 2. My number is less than 100 but larger than 50.
clue 3. My number is the product of three primes, which are all different.
Can some one tell me how to work this problem?
Well, let’s look at the primes 2,3,5,7
We know form C1 that 2 and 7 are in the number. If we have 2*3*7 we get 42, but C2 tells us our number is greater than 50, so nix this. Now look at 2*5*7=70. Does it satisfy C1, C2 and C3?