Verbal Reasoning - Mental Ability Questions

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
BT, DR, FP, ?

From the given alternative words, select the word which cannot be formed using the letters of the given word:

LEGALIZATION

Ramesh is richer than Satish but Jaya is less rich than Ramesh. Ram is less rich than Jaya but richer than Satish, but is not as rich as Ramesh. Ramesh is less rich than Navin. The richest amongst them is?

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?

12 x 6 ÷ 5 + 4 = ?

In the following question, by using which mathematical operators will the expression become correct?
15 _ 3 _ 4 _ 20

X drives 30 km south, then turns right and drives 30km, then turns left and drives 20 km and then turns left and drives 30 km. How far is X from his/her initial position?

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?

m_o_mn_p_no_

Sandeep has a brother named Ankur. Sandeep is the son of Kishan. Baljor is Kishan's father. How is Ankur related to Baljor?