GATE | Sudo GATE 2020 Mock III (24 January 2019) | Question 4
Consider a three digit number abc. Then the probability such that a > b > c is __________ .
(A) 720 / 900
(B) 180 / 900
(C) 120 / 900
(D) 150 / 900
Explanation: There are 9∗10∗10=900 three digit numbers.
In the number abc, the digits are strictly decreasing. So they aren’t equal.
Attention reader! Don’t stop learning now. Practice GATE exam well before the actual exam with the subject-wise and overall quizzes available in GATE Test Series Course.
Learn all GATE CS concepts with Free Live Classes on our youtube channel.
From the available ten digits, select any three. This can be done in 10C3 ways.
Now arrange them in descending order. That’s it. We have a favorable number.
So the probability is,
10C3 / 900 = 120 / 900 = 2 / 15
Option (C) is correct.
Quiz of this Question