The area of the base of a right circular cone is 400π and its height is 15 cm. The curved surface of the cone ( in cm²) is:

In a college 12% of all the students are interested in sports, 10% of the total students are interested in singing and three-fourth of the total students are interested in dancing and remaining 15 students are not interested in any activity, How many total students are there in the college?

Directions:  In the following two equations questions numbered (I) and (II) are given. You have to solve both equations and
Give answer
(a) If x > y
(b) If x ≥ y
(c) If y > x
(d) If y ≥ x
(e) If x = y or no relation can be established

$$ {I.x^{2}=81}$$
$$ {II.(y-9)^{2}}=0$$

A man gives 20% of his money to his eldest son, 30% of remaining he gives to his younger son. 10% of the remaining he gives in a school for poor boys still he has Rs.100.80. Find his total sum. 

If $$  3 ^{2x-y}=3^{x+y}=\sqrt{27}$$ then the value of y is

 Pipe A alone & pipe B alone can fill the same tank in 5 hours and 4 hours respectively. If the ratio of efficiency of pipe A & B together to that of pipe C alone is 9:2, then find time taken by pipe C alone to fill the same tank?

By reducing the circumference of a circle by 50 percent, by what percentage will its area decrease?

The HCF of two numbers is 96 and their LCM is 1296. If one of the numbers is 864, the other is