Question

Select the correct alternative to replace the ?
$371531:5112347::7153163:?$

• A. $9$ $21$ $41$ $81$
• B. $13$ $31$ $63$ $127$
• C. $13$ $29$ $61$ $125$
• D. $9$ $19$ $39$ $79$

Answer 1

Answer: (D)

$9$ $19$ $39$ $79$

3 7 15 31
So, the next number is twice the previous number plus 1
and for next series i.e., 5 11 23 47 we add 2
Similarly for 7 15 31 63 it will be 9 19 39 79.