Alphabet series SSC Multitasking question

What will come in place of the question mark(?) in the following alphabet series based on their positions in the English alphabet? DGH JMN ?VYZ

An operating system that can do multitasking means that_____.

Which of the following will come in place of the question mark (?) in the following letter series based on their positions in english alphabet? AEC, EIG, ? , MQO, QUS

Which of the following will come in place of the question mark (?) in the following letter series based on their positions in english alphabet? UPI ? ODP MBQ IAW

In each of the following questions, a series of number / alphabet is given which follow certain rules. One of the number / alphabet is missing. Choose the missing number / alphabets from the alternatives given below and mark it on your answer - sheet as directed. 18, 24, 21, 27, ?, 30, 27,

In each of the following questions, a series of number / alphabet is given which follow certain rules. One of the number / alphabet is missing. Choose the missing number / alphabets from the alternatives given below and mark it on your answer - sheet as directed. ELFA, GLHA, ILJA, ? , MLNA