A. 52/77
B. 76/155
C. 89/198
D. 7/15
In a class 40% students study History, 25% Civics, 15% both history and Civics. A student fromthe class is selected at random. The probability that he studies history ifit is known that he studies civics is
There are 25 st5amps numbered from 1 to 25 in a box. If a stamp is drawn at random from the box, the probability that the number on the stamp will be a prime number is
The perpendicular distance of radical axis determined by the circles x2+y2+2x+4y-7=0 and x2+y2-6x+2y-5=0 from the origin is
A bag contains 3 red, 4 white and 5 black balls. One ball is drawn at random. If a,b,c are the probabilities of drawing a red a white, a black ball from the bag then the ascending order of a,b,c is
One number is selected at random from 1 to 100. The probability that it is a prime number is
Urn A contains 6 red and 4 black balls and urn B contains 4 red and 6 black balls. One ball is drawn at random from urn A and placed in urn B. Then one ball is drawn at random from urn B and placed in urn A. if one ball is now drawn from urn A, the probability that it is found to be red is
3 persons A,B,C are to speak at a function along with 5 other persons. If the persons speak in random order, the probability that A speaks before B and B speaks before C is
If the plane 2ax-3ay+4az+6=0 passes through the midpoint of the line joining the centres of the spheres x2+y2+z2+6x-8y-2z=13 and x2+y2+z2-10x+4y-2z=8 then a=
A is one of 6 horses entered for a race and is to be ridden by one of two jockeysP and Q. It is 2 to 1 that P rides A, in which case all the horses are likely to win. If Q rides A, his chance is tribled. The probability of A’s winning is
5 different engineering, 4 different mathematics and 2 different chemistry books are placed in a shelf at random. The probability that the books of each kind are all together is