Verbal Reasoning - Mental Ability Questions

If + means division, ­ means multiplication, '÷' means subtraction, x means addition, and < means less than, then which of the following is false?

A series is given, with one word missing. Choose the correct alternative from the given ones that will complete the series.

nature, ensure, tense, spent, spurn, ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

? , Planning, Strategy, Marketing, Finance

Which set of letters when sequentially placed at the gaps in the given letter series shall complete it?

CD_E_DD_CD_E

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

ONU, NKP, MHK, LEF, ?

In the following question, from the given alternative words, select the word which cannot be formed using the letters of the given word.
Nightwalker

A series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series.

4, 9, 16, 25, 36, ?

Three words in bold letters are given in each question, which have something in common among themselves. Out of the four given alternatives, choose the most appropriate description about these three words.

knot: Watt: Fathom