Select the combination of letters that when sequentially placed in the gaps of the given letter series will complete the series.
cd_ab_cd_abb_dda_b

Three of the following four numbers are alike in a certain way and one is different. Pick the number that is different form the rest.

Three of the following four letter-clusters are alike in a certain way and one is different. Pick the odd one out.

Arrange the following words in a logical and meaningful order.
1. Doctor
2.Recovery
3. Hospital
4.Home
5. Sickness
6. Medicine store

Select the word-pair in which the two words are related in the same way as are the two words in the following word-

Mnemonic : Memory

Statements:

Some quadrilaterals are squares.

All squares are rhombuses.

Conclusions:

I. No quadrilateral is a rhombus.

II. All rhombuses are squares.

III. Some quadrilaterals are rhombuses.

If "MARBLES" is coded as "PDUEOHV", then how will "GIN" be coded as? 

Three of the following four word pairs are alike in a certain way and one is different. Pick the odd word out.