I have cows, horses and dogs, a different prime number of each. If I multiply the number of cows (c) by the total of cows and horses (c+h), the product is 120 more than the number of dogs (d), that is: c*(c+h) = 120 + d.
How many of each do I have?
(In reply to
Odds are by ed bottemiller)
Nice explanation ed! I too got the same result upon realizing the special role of '2' here, and yes, 11 and 13 do happen to be consecutive primes separated by 2. Sorry to nit-pick though, but unless I'm missing something here (entirely possible this wet and dreary day:(, how can you say that we're actually looking for (c+2), or (prime+2), to be the second in a 'prime pair', or even a prime number at all? While that happens to be the case here once you hit on the actual solution, couldn't (c+2) really have just been any number, prime or otherwise, until you rule out the possibilities? In other words, very few primes + 2 necessarily = another prime!
re: Odds are
