In the following question, find the missing letters in the given letters.
$$ {D\over 5},{G\over 9},{J\over 14},{M\over20},?$$

Choose the correct alternative from the given ones that will complete the given sequence.
ALN, DNP, GPR, ?

Which of the following numbers will replace the question mark (?) in the given series?

? 11, 35, 107, 323

Select the correct option that will fill in the blank and complete the series.
3, 9, 36, 180, ?

A series is given below. In which a letter pair is not given. Choose the correct alternative from the given ones that will complete the series.
ML, RQ, WV, BA ?

In the following question, select the number which can be placed at the sign of question mark (?) from the given alternatives.
2460, 3570, 4680, ?

Select the number that can replace the question mark (?) in the following series.
423, 407, 439, 391, 455, ?

Select the term that will come next in the following series.
OBE, PDH, QFK, RHN, ?