If A, B and C are mutually exclusive and exhaustive events of a random experiment such that P(B) = P(A) and P(C) = P(B), then P(A ∪ C) equals to
The mean of four observations is 3. If the sum of the squares of these observations is 48, then their standard deviation is
The condition that f(x) = a + bx2 + cx + d has no extreme value, is
D.
If there is an error of ± 0.04cm in the measurement of the diameter of a sphere, then the approximate percentage error in its volume, when the radius is 10cm, is