Verbal Reasoning - Mental Ability Questions

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
efg _ _ eff _ ghhe _ eff _ gggh _ h

In a certain code language, "RAIN" is written as "OHBQ". How is "SUMMER" written in that code language?

In a certain code language, "MATCH" is written as "NYWYM" and "BOARD" is written as "CMDNI". How is "PRINT" written in that code language?

In a certain code language, "DISORDER" is written as "OSIDREDR". How is "PRACTICE" written in that code language?

Priya's birthday is on Tuesday 11th April. On what day of the week will be Rani's Birthday in the same year if Rani was born on 31st August?

In the English alphabet, which letter is 13th from right end?

A plane flies 100 km West, then it turns South and flies 150 km, then it turns West and flies 300 km, then it turns to its right and flies 150 km. Where is it now with reference to its starting position?

In the following question, select the missing number from the given series.
21, 25, 52, 68, 193, ?