Direction: what should come in place at question mark(?).

$$ {\sqrt{4489}+(71)^{2}-(?)^{2}=2707}$$

The given pie chart shows the percentage of students enrolled for the courses A, B, C, D and E in a university and the table shows the percentage of students that passed, out of the enrolled students.
Total Students=60,000

How many students passed in Course C?

Two pipes, A and B, can fill a tank in X minutes and 6 minutes, respectively. If both the pipes are used together, then they take 1.5 minute to fill the tank. Find the value of X.

P and Q are center of two circles with radii 9 cm and 2 cm respectively, where PQ = 17 cm, R is the center of another circle of radius x cm, which touches each of the above two circles externally. If ∠PRQ = 90 °, then the value of x is 

A is 4 years younger than B. B is 12 years younger than C. 4 years hence the ratio between C and A is 9:5, Find the age of B.

The distance between the centers of two circles having radii 4.5 cm. and 3.5 cm. respectively is 10 cm. What is the length of the transverse common tangent of these circles?

B walks at a speed of 9 km/h and after 9 hours of its start, C follows him on his cycle at a speed of 18 km/h. At what distance from the starting point will C catch B?

Two numbers x and y (x>y) such that their sum is equal to three times their difference. Then value of $$3xy\over 2(x^2-y^2$$ will be