Which of the following statement is true about an operating system (OS)?

12 : 156 : : 19 : ?

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.

Select the related word/letters/number from the given alternatives.

LHX: OEA : : PFT : ?

Find the missing term in the following question:

Select the combination of numbers that when placed sequentially in the blanks of the given series will complete the series.

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

24, 48, 51, 204, 209, ?

Select the missing number from the given responses. 

In the following expression find the missing term:

Find the missing term?

Find the missing number.

20, 30, 42, 56, 72, ?