Q4.An urn contains 5 red and 5 black balls. A ball is drawn at random, its colour is noted and is returned to the urn. Moreover, 2 additional balls of the colour drawn are put in the urn and then a ball is drawn at random. The probability that the second ball drawn is red will be
Q8.Two vertices of a triangle have position vectors 3iˆ + 4 ˆj − 4kˆ and 2iˆ + 3 ˆj + 4kˆ. If the position vector of the centroid is iˆ + 2 ˆj + 3kˆ, then the position vector of the third vertex is