English

There are four bus routes between A and B; and three bus routes between B and C. A man can travel round-trip in number of ways by bus from A to C via B. If he does not want to use a bus route

Advertisements
Advertisements

Question

There are four bus routes between A and B; and three bus routes between B and C. A man can travel round-trip in number of ways by bus from A to C via B. If he does not want to use a bus route more than once, in how many ways can he make round trip?

Options

  • 72

  • 144

  • 14

  • 19

MCQ
Advertisements

Solution

72

Explanation:

In the following figure:

There are 4 bus routes from A to B and 3 routes from B to C.

Therefore, there are 4 × 3 = 12 ways to go from A to C.

It is round trip so the man will travel back from C to A via B.

It is restricted that man can not use same bus routes from C to B and B to A more than once.

Thus, there are 2 × 3 = 6 routes for return journey.

Therefore, the required number of ways = 12 × 6 = 72.

shaalaa.com
  Is there an error in this question or solution?
Chapter 7: Permutations and Combinations - Solved Examples [Page 120]

APPEARS IN

NCERT Exemplar Mathematics [English] Class 11
Chapter 7 Permutations and Combinations
Solved Examples | Q 13 | Page 120

Video TutorialsVIEW ALL [1]

RELATED QUESTIONS

How many 3-digit numbers can be formed from the digits 1, 2, 3, 4 and 5 assuming that repetition of the digits is allowed?


A coin is tossed 3 times and the outcomes are recorded. How many possible outcomes are there?


A Signal is generated from 2 flags by putting one flag above the other. If 4 flags of different colours are available, how many different signals can be generated?


How many two letter words can be formed using letters from the word SPACE, when repetition of letters is allowed?


How many two letter words can be formed using letters from the word SPACE, when repetition of letters is not allowed?


How many three-digit numbers can be formed from the digits 0, 1, 3, 5, 6 if repetitions of digits are not allowed?


A letter lock contains 3 rings, each ring containing 5 different letters. Determine the maximum number of false trials that can be made before the lock is opened?


If numbers are formed using digits 2, 3, 4, 5, 6 without repetition, how many of them will exceed 400?


A school has three gates and four staircases from the first floor to the second floor. How many ways does a student have to go from outside the school to his classroom on the second floor?


How many five-digit numbers formed using the digit 0, 1, 2, 3, 4, 5 are divisible by 5 if digits are not repeated?


Select the correct answer from the given alternatives.

A college offers 5 courses in the morning and 3 in the evening. The number of ways a student can select exactly one course, either in the morning or in the evening


Answer the following:

A hall has 12 lamps and every lamp can be switched on independently. Find the number of ways of illuminating the hall.


There are 3 types of toy car and 2 types of toy train available in a shop. Find the number of ways a baby can buy a toy car and a toy train?


Three persons enter into a conference hall in which there are 10 seats. In how many ways they can take their seats?


In how many ways 5 persons can be seated in a row?


Four children are running a race:
In how many different ways could they finish the race?


Count the number of three-digit numbers which can be formed from the digits 2, 4, 6, 8 if repetitions of digits is allowed


How many numbers are there between 100 and 500 with the digits 0, 1, 2, 3, 4, 5? if the repetition of digits is not allowed


How many three-digit odd numbers can be formed by using the digits 0, 1, 2, 3, 4, 5? if the repetition of digits is not allowed


Count the numbers between 999 and 10000 subject to the condition that there are no restriction


To travel from a place A to place B, there are two different bus routes B1, B2, two different train routes T1, T2 and one air route A1. From place B to place C there is one bus route say B1, two different train routes say T1, T2 and one air route A1. Find the number of routes of commuting from place A to place C via place B without using similar mode of transportation


How many strings can be formed using the letters of the word LOTUS if the word either starts with L or ends with S?


Find the value of 4! + 5!


Find the value of `(("n" + 3)!)/(("n" + 1)!)`


Evaluate `("n"!)/("r"!("n" - "r")!)` when n = 6, r = 2


Choose the correct alternative:
The number of 5 digit numbers all digits of which are odd i


Choose the correct alternative:
The number of five digit telephone numbers having at least one of their digits repeated i


In a class, there are 27 boys and 14 girls. The teacher wants to select 1 boy and 1 girl to represent the class for a function. In how many ways can the teacher make this selection?


How many numbers are there between 99 and 1000 having 7 in the units place?


Out of 18 points in a plane, no three are in the same line except five points which are collinear. Find the number of lines that can be formed joining the point


The number of different four-digit numbers that can be formed with the digits 2, 3, 4, 7 and using each digit only once is ______.


The number of six-digit numbers, all digits of which are odd is ______.


Three letters can be posted in five letterboxes in 35 ways.


There will be only 24 selections containing at least one red ball out of a bag containing 4 red and 5 black balls. It is being given that the balls of the same colour are identical.


The number of all four digit numbers which begin with 4 and end with either zero or five is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×