Multiple choice

In the following number series, a wrong number is given. Find out that wrong number. 10 120 340 770 1660 3420

  1. 120

  2. 10

  3. 3420

  4. 1660

  5. 770
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E Correct answer
Explanation

The series follows the pattern n² + (n+2)² for n = 1, 5, 9, 13, 17: 1+9=10, 25+49=74 (should be 120), 81+121=202 (should be 340), 169+225=394 (should be 770), 289+361=650 (should be 1660). The term 770 should be 772 following the pattern of differences 110, 220, 440, 880, making 770 the wrong number.

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