### Question

**Find the wrong number in the given number series?10, 21, 54, 109, 189**

A. 189

B. 109

C. 54

D. 21

**Answer:** A

**Solution:**

The given number series is 10, 21, 54, 109, 189

The series follows a pattern that 10 + 11 = 21

21 + 33 = 54

54 + 55 = 109

109 + 77 = 186

Hence the wrong number in the given number series is **189**.