JEE Main20244 Apr 2024Morning ShiftMathematicsProbabilityActual
Three urns A, B and C contain 7 red, 5 black; 5 red, 7 black and 6 red, 6 black balls, respectively. One of the urn is selected at random and a ball is drawn from it. If the ball drawn is black, then the probability that it is drawn from urn A is :
Options
- A5 18
- B5 16
- C4 17
- D7 18
Correct answer
A. 5 18
Step-by-step solution
array ccc A & B & C 7 R , 5 ~B & 5 R , 7 ~B & 6 R , 6 ~B array aligned & P ( B )= 1 3 5 12 + 1 3 7 12 + 1 3 6 12 & required probability = 1 3 5 12 1 3 [ 5 12 + 7 12 + 6 12 ] = 5 18 aligned