Let x = prime number

x < 19

since the sum of the digits is > 7, then x >= 11 since it is prime

possible primes are 11,13,17

sorry I could not come up with an equation to prove this, but the answer has to be 17 since it is the only prime whose digits are greater that 7 and also less than 19.

x < 19

since the sum of the digits is > 7, then x >= 11 since it is prime

possible primes are 11,13,17

sorry I could not come up with an equation to prove this, but the answer has to be 17 since it is the only prime whose digits are greater that 7 and also less than 19.