Solution:The pattern followed here is :(1st number × 2nd number) + 5 = 3rd number
(12, 11, 137) → (12 × 11) + 5 ⇒ 132 + 5 = 137
(17, 21, 362) → (17 × 21) + 5 ⇒ 357 + 5 = 362
Similarly,
(21, 25, 530) → (21 × 25) + 5 ⇒ 525 + 5 = 530
Hence, (21, 25, 530) is the correct answer.