Home
Class 12
MATHS
There are four pairs of shoes of differe...

There are four pairs of shoes of different sizes. Each of the 8 shoes can be coloured with one of the four colours. Black, Brown, White and Red. The number of ways the shoes can be coloured so that in atleast three pairs, the left shoe and the right shoe do not have the same colour is

A

`12^(4)`

B

`28xx12^(3)`

C

`16xx12^(3)`

D

`4xx12^(3)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem of coloring the shoes such that at least 3 pairs have different colors for the left and right shoes, we can break down the solution step by step. ### Step 1: Understanding the Problem We have 4 pairs of shoes, which means there are 8 individual shoes. Each shoe can be colored in one of 4 colors: Black, Brown, White, and Red. We need to find the number of ways to color the shoes such that at least 3 pairs have different colors for the left and right shoes. ### Step 2: Total Ways to Color the Shoes First, let's calculate the total number of ways to color all 8 shoes without any restrictions. Each shoe can be one of 4 colors, so the total number of ways to color all shoes is: \[ 4^8 \] ### Step 3: Counting the Cases Now, we need to consider the cases where at least 3 pairs have different colors. We can break this down into two cases: 1. Exactly 3 pairs have different colors. 2. All 4 pairs have different colors. ### Step 4: Case 1 - Exactly 3 Pairs with Different Colors To find the number of ways to color the shoes such that exactly 3 pairs have different colors, we can: 1. Choose 3 pairs from the 4 pairs. The number of ways to choose 3 pairs from 4 is given by: \[ \binom{4}{3} = 4 \] 2. For each of the 3 chosen pairs, we can color them in different colors. The first shoe can be colored in any of the 4 colors, and the second shoe must be a different color (3 choices). Thus, for each of the 3 pairs: \[ 4 \times 3 = 12 \text{ ways} \] Therefore, for 3 pairs, the total ways is: \[ 12^3 \] 3. The remaining pair can be colored in any of the 4 colors (both shoes can be the same color). Thus, there are: \[ 4 \text{ ways} \] Combining these, the total number of ways for this case is: \[ \text{Total for Case 1} = \binom{4}{3} \times 12^3 \times 4 = 4 \times 12^3 \times 4 = 16 \times 12^3 \] ### Step 5: Case 2 - All 4 Pairs with Different Colors For the case where all 4 pairs have different colors: 1. All pairs can be colored in the same way as in the previous case, but now we have 4 pairs. The first shoe can be colored in any of the 4 colors, and the second shoe must be a different color (3 choices). Thus, for each of the 4 pairs: \[ 4 \times 3 = 12 \text{ ways} \] Therefore, for 4 pairs, the total ways is: \[ 12^4 \] ### Step 6: Combining Both Cases Now, we combine the results from both cases to find the total number of ways to color the shoes such that at least 3 pairs have different colors: \[ \text{Total} = 16 \times 12^3 + 12^4 \] ### Step 7: Final Calculation To simplify: \[ 12^4 = 12 \times 12^3 \] Thus: \[ \text{Total} = 16 \times 12^3 + 12 \times 12^3 = (16 + 12) \times 12^3 = 28 \times 12^3 \] ### Conclusion The number of ways to color the shoes such that at least 3 pairs have different colors is: \[ \boxed{28 \times 12^3} \]
Promotional Banner

Topper's Solved these Questions

  • PERMUTATIONS & COMBINATIONS

    FIITJEE|Exercise ASSIGNMENT PROBLEMS (OBJECTIVE) LEVEL II|23 Videos
  • PERMUTATIONS & COMBINATIONS

    FIITJEE|Exercise COMPREHENSIONS|9 Videos
  • PERMUTATIONS & COMBINATIONS

    FIITJEE|Exercise ASSIGNMENT PROBLEMS (SUBJECTIVE) LEVEL -II|15 Videos
  • PARABOLA

    FIITJEE|Exercise NUMERICAL BASED|5 Videos
  • PROBABILITY

    FIITJEE|Exercise Exercise 7|2 Videos

Similar Questions

Explore conceptually related problems

A new flag is to be designed with six vertical strips using some or all of the colours yellow, green,blue and red.Then,the number of ways this can be done such that no two adjacent strips have the same colour is

A new flag is to be designed with six vertical stripes using some or all of the colour yellow, green, blue and red. Then, the number of ways this can be made such that no two adjacent stripes have the same colour is

A rack has 5 different pairs of shoes.The number of ways in which 4 shoes can be chosen from it so that there will be no complete pair is

The number of ways four boys can be seated around a round talble in four chairs of ditterent colours, is

You are given 8 balls of different colour (black,white ......). The number of ways in which these balls can be arranged in a row so that the two balls of particular colour (say red and white) may never come together is-

FIITJEE-PERMUTATIONS & COMBINATIONS-ASSIGNMENT PROBLEMS (OBJECTIVE) LEVEL I
  1. The number of sets of three distinct elemetns that can be chosen from ...

    Text Solution

    |

  2. In a group of boys, two boys are brothers and six more boys are pre...

    Text Solution

    |

  3. There are four pairs of shoes of different sizes. Each of the 8 shoes ...

    Text Solution

    |

  4. There are m copies each ofn different books in a university library. T...

    Text Solution

    |

  5. The value of (sum(i=0)^(100).^(k)C(1).^(m-k)C(100-i)((k-i)/(m-100)))/(...

    Text Solution

    |

  6. Number of natural numbers lt2.10^(4), which can be formed with the dig...

    Text Solution

    |

  7. The letters of the word DRAWER are arranged in alphabeticla ordr. The ...

    Text Solution

    |

  8. The number of permuta!ons of the letters of the word HINDUSTAN such th...

    Text Solution

    |

  9. 4 points out of 8 points in a plane are collinear. Number of different...

    Text Solution

    |

  10. Find the three-digit odd numbers that can be formed by using the digit...

    Text Solution

    |

  11. The number of divisors of 3630, which have a remainder of 1 when divid...

    Text Solution

    |

  12. The number of ways in which 15 boys and 2 girls can sit in a row such ...

    Text Solution

    |

  13. The number of rational numbers p/q, where p, q in [1,2,3, 4,5, 6} is

    Text Solution

    |

  14. Let S={1,2,3,....., 100}. The number of non-empty subsets A of S such ...

    Text Solution

    |

  15. On a railway there are 20 stations. The number of different tickets re...

    Text Solution

    |

  16. .^(n)C(r)+2.^(n)C(r-1)+.^(n)C(r-2)=

    Text Solution

    |

  17. How many different nine digit numbers can be formed from the numebr 22...

    Text Solution

    |

  18. A seven-digit number without repetition and divisible by 9 is to be...

    Text Solution

    |

  19. The number of ordered pairs (m,n)(m,n epsilon {1,2,……..20}) such that ...

    Text Solution

    |

  20. The number of arrangements of the letters of the word BANANA in whi...

    Text Solution

    |