Mathematics Tes...

If the standard deviation of x₁, x₂, …, x_n is 3.5, then the standard deviation of – 2x₁ – 3, – 2x₂ – 3, …, – 2x_n – 3 is:

Consider three observations a, b and c such that b = a + c. If the standard deviation of a + 2, b + 2, c + 2 is d, then which of the following is true?

In how many different ways can the letters of the word 'GEOGRAPHY' be arranged such that the vowels must always come together?

The equations ax + 9y = 1 and 9y - x - 1 = 0 represent the same line if a =

If y = y(x) is the solution of the differential equation  such that y(0) = 0, then y(1) is equal to:

The mean and variance of a binomial distribution are 4 and 2, respectively. What is the probability of two successes?

The solutions of the equation cos²x + cos²2x + cos²3x = 1 are given by

If a plane bisects the line segment joining the points (1, 2, 3) and (-3, 4, 5) at right angles, then this plane also passes through the point

The value of k for which the points A (1, 0, 3), B (– 1, 3, 4), C (1, 2, 1) and D (k, 2, 5) are coplanar, is

A unit tangent vector at t = 2 on the curve x = t² + 2, y = 4t³ – 5, z = 2t² – 6t is