Question

Insert the missing number: 7, 26, 63, 124, 215, 342, (....)

• A. 391
• B. 421
• C. 511
• D. 451
• E.

Hint:

Look at both the first and second differences in the series to identify the pattern of increase.

Answer 1

The Correct Option is C

The series follows a pattern where the differences between consecutive numbers increase in a systematic way: - \( 26 - 7 = 19 \) - \( 63 - 26 = 37 \) - \( 124 - 63 = 61 \) - \( 215 - 124 = 91 \) - \( 342 - 215 = 127 \) The first differences are: \( 19, 37, 61, 91, 127 \). Next, the differences between these first differences are: - \( 37 - 19 = 18 \) - \( 61 - 37 = 24 \) - \( 91 - 61 = 30 \) - \( 127 - 91 = 36 \) The second differences are: \( 18, 24, 30, 36 \), which increase by 6. So, the next second difference is: \[ 36 + 6 = 42. \] Adding this to the last first difference: \[ 127 + 42 = 169. \] Thus, the next number in the series is: \[ 342 + 169 = 511. \]