Find the number that can replace question mark (?) in the series given below.
7, 12, 32, 122, ?, 3602, 25202नीचे दी गई श्रेणी में प्रश्नवाचक चिह्न (?) के स्थान पर आने वाली संख्या ज्ञात कीजिए।
7, 12, 32, 122, ?, 3602, 25202

1. A602
2. B610
3. C702
4. D622

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Show answer & explanation

Correct answer: A. 602

Explanation

Subtract 2 from every term: 5, 10, 30, 120, ?, 3600, 25200. These are multiplied by 2, 3, 4, 5, 6, 7 successively. So the missing reduced term = 120 × 5 = 600, and the actual term = 600 + 2 = 602 (check: 600 × 6 = 3600 and 3600 × 7 = 25200).प्रत्येक पद में से 2 घटाइए: 5, 10, 30, 120, ?, 3600, 25200। ये क्रमशः 2, 3, 4, 5, 6, 7 से गुणा होते जाते हैं। अतः लुप्त पद = 120 × 5 = 600 तथा वास्तविक पद = 600 + 2 = 602 (जाँच: 600 × 6 = 3600 और 3600 × 7 = 25200)।