In the adjoining figure, the lines represent one-way roads allowing travel only northwards or only westwards. Along how many distinct routes can a car reach point B from point A?
Explanation:
To reach point B from A, the car has to take a northward route thrice and a westward route five times. Thus we can visualise a set of 8 routes out of which 3 will be northward and 5 westward.
The number of ways in which the car can reach point B from A is a permutation of 8 routes, 5 (W) and 3 (N) of which are repeated.
Thus, number of ways = 8!3!×5! = 56
Hence, option (b).
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.