Verbal Reasoning - Mental Ability Questions

In the following question, select the missing number from the given series.
19, 38, ?, 228, 684, 1368

A boy travels 4 km towards south and then takes a right turn travels another 3 km in that direction. How far and in which direction is he now from his original position?

Select the related word/letters/number from the given alternatives.
DB: IC:: YE: ?

If 4 x 9 x 3 = 4 and 5 x 3 x 1 = 3, then
9 x 9 x 7 = ?

In the following question, select the related letters from the given alternatives.
FS : LY : : IV : ?

In a certain code language, "TIRED" is written as "56" and "BRAIN" is written as "44". How is "LAZY" written in that code language?

If in a certain language TEACHER is coded as QBXZEBO, then how is STUDENT coded in the same language?

In the following question, select the related number pair from the given alternatives.
534 : 2 : : ? : ?