Question

Find out the wrong number in the given series:
51, 27, 61, 122, 213, 340, 509

• A. 27
• B. 61
• C. 122
• D. 509

Hint:

In series problems, look for alternating addition, subtraction, multiplication, or division patterns between numbers.

Answer 1

The Correct Option is A

Let's analyze the given series: 51, 27, 61, 122, 213, 340, 509 
The pattern in the series seems to involve alternating between addition and multiplication. 
1. From 51 to 27, the number is divided by 2, giving us 27. 
2. Then, from 27, we add 34 to get 61. 
3. From 61, we double it to get 122. 
4. Then, from 122, we add 91 to get 213. 
5. From 213, we double it to get 340. 
6. From 340, we add 169 to get 509. 
Since the alternating pattern involves both addition and multiplication, and 27 doesn't fit into the pattern, the wrong number is 27. 
Thus, the correct answer is (A) 27.