23 15 12 X 24 49 If 'X' is the resultant of the first row, what is the resultant of the second row?

Rules
(i) (2-digit odd number) + (2-digit odd number)
(ii) 2-digit even number → 2-digit perfect square odd number then, (odd number) - (Even number)
(iii) (3-digit number) ÷ (2-digit number)
(iv) (Prime number) + (Even number)
(v) (Even number) x (Even number)
Solution:
1st Row   23     15     12 ⇒ 23 + 15 = 38
[rule (i)]     ⇒ 38 x 12 = 456     [rule (v)]
2nd Row   X   24   49 ⇒ 456   24   49
⇒ 456 ÷ 24 = 19 [rule (iii)] ⇒ 19 + 49 = 68     [rule (i)]
∴ Resultant of second row = 68