Direction: In each of the following questions, a number series is given in which one number is wrong. You have to find out that number and have to follow the new series which will be started by that number. By following this, which will be the 2nd number of the new series?
-
2, 7, 19, 43, 99, 209, 431
-
- 181
- 183
- 87
- 85
- None of these
Correct Option: C
The given series is in the below pattern,
First term = 2
Second term = ( First term × 2 ) + 3
⇒ Second term = ( 2 × 2 ) + 3 = 7 ;
Third term = ( Second term × 2 ) + 5
⇒ Third term = ( 7 × 2 ) + 5 = 19
Similarly , we can calculate all others terms also.
Fourth term = ( Third term × 2 ) + 7
⇒ Fourth term = ( 19 × 2 ) + 7 = 43 , is wrong.it should be 45 as fourth term .
Fifth term = ( Fourth term × 2 ) + 9
⇒ Fifth term = ( 45 × 2 ) + 9 = 99 ;
Sixth term = ( Fifth term × 2 ) + 11
⇒ Sixth term = ( 99 × 2 ) + 11 = 209 ;
Seventh term = ( Sixth term × 2 ) + 11
⇒ Seventh term = ( 209 × 2 ) + 13 = 431
New series is given as -
First term = 43 × 2 + 3 = 89;
Second term = 89 × 2 + 5 = 181.
Hence Second term of new series is 181.
