Which letter-cluster will replace the question mark (?) to complete the given series?

abCD, fgHI, ?, stUV, abCD

In the following question below are given some statements followed by some conclusions based on those statements. Taking the given statements to be true even if they seem to be at variance from commonly known facts. Read all the conclusions and then decide which of the given conclusion logically follows the given statements.

Statements:
 I. All A are R.
 II. All R are C.

Conclusions:
 I. All A are C.
 II. Some R are A.
 III. No C is R.

Four clusters have been given out of which three are alike in some manner and one is different. Select the one that is different.

Options

Select the option that is related to the third word in the same way as the second word is related to the first word. (The words must be considered as meaningful English words and must not be related to each other based on the number of letters/number of consonants/vowels in the word)
 Knife : Cut :: Ladle : ?

By interchanging the given two signs which of the following equation will be not correct?
 – and × 

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

29, 33, ?, 113, 369

Study the given pattern carefully and select the number that can replace the question mark (?) in it.
 First row: 18, 9, 27
 Second row: 40, 36, 140
 Third row: 40, 13, ?
 (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 – Operations on 13 such as adding / subtracting / multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed)

By interchanging the given two signs which of the following equation will be not correct?
 –   and ÷