A boat goes 30 km upstream and 44 km downstream in 10 hours. In 13 hours, it can go 40 km upstream and 55 km downstream. The speed of the boat in still water is. 

Each question below is followed by two statements A and B. You have to determine whether the data given in the statement is sufficient for answering the question. You should use the data and your knowledge of Mathematics to choose the best possible answer.
Give answer (A) if the statement A alone is sufficient to answer the question, but statement B alone is not sufficient.
Give answer (B) if the statement B alone is sufficient to answer the question, but statement A alone is not sufficient.
Give answer (C) if both statements A and B together are needed to answer the question.
Give answer (D) if either the statements A alone or statement B alone is sufficient to answer the question
Give answer (E) if you cannot get the answer from the statements A and B together, but need even more data.

Triangle ABC has angle BAC equal to 90°. What is the measure of the angle ABC?
A. The angle ACB is 35°
B. The angle CBA is 55°

If x+y=10 and xy=4, then what is the value of x⁴+y⁴=?

The side of a square is 8 cm. If a square is made by joining the mid points of each sides of this square and this process goes up to infinity. Calculate the sum of areas of all the squares made.

What is the minimum number of square marbles required to tile a floor of length 5 meters 78 cm. and width 3 meters 74 cm?  

Find the sum of all prime numbers between 10 and 90.

A person swims a distance of 28 km. in the direction of stream in 5 hours and a distance of 13 km. in 5 hours against the stream. What is the velocity of the stream?

Find the single equivalent discount for successive discounts of 12%, 18% and 25% on the marked price of a car.