Subject: General Aptitude · Chapter: Probability · Exam: · Marks: · Difficulty:
A bag contains 6 red balls 11 yellow balls and 5 pink balls. If two balls are drawn at random from the bag. One after another what is the probability that the first ball is red and second ball is yellow. [IBPS-Bank PO (Pre.) Exam, 2015]
(a)$\frac{1}{14}$
(b)$\frac{2}{7}$
(c)$\frac{5}{7}$
(d)$\frac{3}{14}$
(e)None of these
Answer
Answer (as printed): B
Explanation
Number of red balls = 6 Number of yellow ball = 11 Number of pink balls = 5 Total number of balls = 6 + 11 + 5 = 22 22! 22! Total possible outcomes = n ( E ) = 22 $\mathrm{C_{2}}$ = = 2! ( 22 − 2 ) ! 2!× 20! 22 × 21 = = 231 2 ×1 Number of favourable outcomes QUANTITATIVE APTITUDE = n ( s) = $\mathrm{C_{1}}$ × $\mathrm{C_{1}}$ = 6 × 11 = 66 6 11 n ( E ) 66 2 Required probability = = = n ( S ) 231 7