Directions : In each of the following letter series, some of the letters are missing which are given in that order as one of the alternatives below it.

ab ---b -bbaa- 

aa_baa_aaa_ba_ba

A tourist travelled 10 km in the west and went 4 km after turning to the left. Then he travelled 4 km. in the East and went 5 km. after turning to the right. Then he travelled 6 km. after turning to his left. Find his direction regarding the starting point.

Dinesh is older than Ramesh. Boman is younger than Dinesh. Who is the youngest of all. 

If 9 θ 11 α 2 = 40 and 13 θ 12 α 3 = 75, then 40 θ 41 α 5 = ?

If A = 2, M=26, Z=52, then BET =?

Find the missing number?

A cyclist goes 30 km to North and then turning to East he goes 40 km. Again, he turns to his right and goes 20 km. After this he turns to his right and goes 40 km. How far is he from his starting point?