The rate at which the temperature changes as air rises

Find the missing number.

Find the missing term in the given series:

Find the missing number by analysing the pattern followed by the numbers in each row.

In the following question, a series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

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

First row: 4, 6, 18

Study the given matric carefully and select the number from among the given options that can replace the question mark (?) in it.

Find the missing letter.

In the following question, a series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.