Railways PYQCBT 1 2016

RRB NTPC · Question 94

Statements followed by some conclusions are given below. Statements: 1. A bag has 2 white, 3 black, 4 red and 6 green balls. 2. 1 ball selected at random from the bag. Conclusions: I. The probability that a black ball is selected is 1/5 II. The probability that a red ball is selected is 6/15 Find which of the conclusions logically follows from the given statement A. Only conclusion I follows. B. Only conclusion II follows. C. Both I and II follow. D. Neither I nor II follows.

  1. B

  2. D

  3. C

  4. A

Show answer & explanation

Answer: (D) A

Explanation

The bag has 2 + 3 + 4 + 6 = 15 balls. P(black) = 3/15 = 1/5, so conclusion I is correct. P(red) = 4/15, not 6/15 (6/15 is the probability of green), so conclusion II is wrong. Only conclusion I follows.