CSATPermutation, Combination & ProbabilityLinear Permutation2017

If 2 boys and 2 girls are to be arranged in a row so that the girls are not next to each other, how many possible arrangements are there?

Correct Answer: Option C

Explanation

To solve this elegantly, we recall the 'Not Next To' constraint pattern from 2014 and 2016 [16, 42]. The most direct tool for this is the **Gap Method**. **Step 1: Arrange the Boys (

More Permutation, Combination & Probability PYQs

Three numbers x, y, z are selected from the set of the first seven natural numbers such that x > 2y > 3z. How many such distinct triplets (x, y, z) are possible?
In how many ways can a batsman score exactly 25 runs by scoring single runs, fours and sixes only, irrespective of the sequence of scoring shots?
ABCD is a square. One point on each of AB and CD; and two distinct points on each of BC and DA are chosen. How many distinct triangles can be drawn using any three points as vertices out of these six points?
In an examination, the maximum marks for each of the four papers namely P, Q, R and S are 100. Marks scored by the students are in integers. A student can score 99% in n different ways. What is the value of n ?
How many distinct 8-digit numbers can be formed by rearranging the digits of the number 11223344 such that odd digits occupy odd positions and even digits occupy even positions?
A flag has to be designed with 4 horizontal stripes using some or all of the colours red, green and yellow. What is the number of different ways in which this can be done so that no two adjacent stripes have the same colour?

View all Permutation, Combination & Probability questions →

Master UPSC Revision

Get 10,000+ topic-wise MCQs, spaced repetition, daily CSAT challenges, and detailed performance analytics.

Coming Soon to Play Store