What is the currency of

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

Find the next term / numbers in the given series?

54, 46, 40, 36, ?

Find the missing number.

. 

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, ?

In the following question, select the missing number from the given alternatives.

45, 15, 60, 75, 135, ?

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

Find the missing letter.

 Find the missing number. 

Choose the correct alternative that will complete the given number series. 2, 9, 28, 65, ?, 217