Question

In the following number series, a wrong number is given. Find the wrong number.
1, 2, 6, 21, 84, 445, 2676

• A. 6
• B. 21
• C. 2676
• D. 84
• E. 445

Answer 1

The correct option is D 84

2676 = 6 $\times$ 445 + 6; 445 $\ne$ 5 $\times$ 84 + 5
84 $\ne$ 4 $\times$ 21 + 4; 21 = 3 $\times$ 6 + 3
6 = 2 $\times$ 2 + 2; 2 = 1 $\times$ 1 + 1
Obviously, 84 is wrong and should be replaced by 4 $\times$ 21+ 4 = 88
With this, 445 = 5 $\times$ 88 + 5.