92,   51,   21,   13.5,    x,   4.25

Select the option that represents the letters which, when sequentially placed from left to right in the blanks below, will complete the letter series.

In a certain code language, 'DOSIER' is written as 'DEIORS' and 'LOGIC' is written as 'CGILO'. How will 'CORTEX' be written in that language?

Select the figure that will come next in the following series. 

Three of the following letter-clusters are alike in some manner and one is different.

Select the one that is different.

If '+' means '×', '×' means '–', '–' means '÷' and '÷' means '+', then what will come in place of the (?) in the following equation?

If in a code language, 'HOME' is written as 'LROF' and 'EYE' is written as 'HAF' and 'SO' is written as 'UP', how will 'HOUSE' be written in that language?

If HOARDING is coded as NGQZHCFM, then how would TREATISE be coded?