A man takes 2.2 times as long to row a distance upstream as to row the same distance downstream. If he can row 55km downstream in 2 hours 30 minutes, what is the speed of the boat is still water ? (in km/h)

Directions (next five questions) : Study the following information to answer the given questions.

This data is regarding number of Junior College students, Graduate students and Post-Graduate students (PG) only, studying in colleges A,B,C and D.

The respective ratio between the total number of students studying in the colleges A,B,C and D is 3:5:2:5. In college A, 40% of the total number of students is Junior College students. Out of the remaining, the respective ratio between the number of Graduate students and number of PG graduates is 5:4.

In college B, 2/5th of the total number of students are Junior College students. Out of the remaining, the respective ratio between the number of Graduate students and number of post graduate students is 5:3. In college C, 50% of the total number of students is Junior College students. Out of the remaining, 5/8th are Graduate students and the remaining are PG students.

In college D, 35% of the total number of students is Graduate students, 8/13th of the remaining students are Junior College students and the rest 1500 are PG students.