The branch of Horticulture that deals with the

Find the missing number.

Select the number from among the given option that can replace the question mark (?) in the following series.

6, 31, 126, 381, 766, ?

Select the number from among the given option that can replace the question mark (?) in the following series.

4, 21, 86, 261, 526, ?

What number should replace the question mark? 

Find the missing number.

Study the given pattern carefully and select the number that can replace the question mark (?) in it.  

First row: 4, 6, 18

Find the missing term in the following question:

Find the missing numbers.

In each of the following questions select the related letter/word/figure/number from the given alternatives.

JRH : ? : : KOV : 51