Mala has the colouring book in which each English letter is drawn two ...
This question is slightly ambigous. So first let us understand what question is asking. So in a book, we have letters A-Z and each letter is printed twice, so there are 52 letters. Now we have to color each letter, so we need a pair of colors for that, because each letter is printed twice. Also in a pair, both colors can be same. Now condition is that a pair of colors can't be used more than once.
So suppose Mala has 3 colors : Red, Blue, Green. She can color as follows : 1:(Red,Red), 2:(Blue,Blue), 3:(Green,Green), 4: (Red,Blue), 5: (Red,Green),
6 : (Blue,Green).
Now we don't have more pairs of colors left, we have used all pairs, but could color only 6 letters out of 26. So question is to find minimum no. of colors, so that we could color all 26 letters.
So if Mala has k colors, she can have k pairs of same colors, thus coloring k letters, then kC2 other pairs of colors, thus coloring kC2 more letters.
So total no. of letters colored
So we want
so option (C) is correct.
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Mala has the colouring book in which each English letter is drawn two ...
Problem Analysis:
Mala has a coloring book with 52 prints, each representing an English letter. There are two prints of each letter. Mala wants to color each print with one of k colors, such that the color pairs used to color any two letters are different. The goal is to find the minimum value of k that satisfies this requirement.
Solution:
To solve this problem, we need to consider the worst-case scenario, where we need to use the maximum number of distinct color pairs for different letters. Let's analyze this scenario:
Worst-case scenario:
In the worst-case scenario, each letter print needs to be colored with a different color pair. Since there are 52 prints, we need to find the maximum number of distinct color pairs required for 52 prints.
Calculating the maximum number of distinct color pairs:
To calculate the maximum number of distinct color pairs required for 52 prints, we can use the formula for the sum of the first n natural numbers: sum = n * (n + 1) / 2.
Let's assume the maximum number of color pairs required is x. Therefore, we have the equation:
x = 1 + 2 + 3 + ... + n
Using the formula for the sum of the first n natural numbers, we have:
x = n * (n + 1) / 2
Now, we need to find the minimum value of n that satisfies the equation:
x = n * (n + 1) / 2 >= 52
Simplifying the equation:
n * (n + 1) >= 104
n^2 + n - 104 >= 0
Solving this quadratic inequality, we find that n >= 10.2 (approximately).
Since n must be an integer, we can conclude that the minimum value of n is 11.
Calculating the minimum value of k:
Now that we have the maximum number of distinct color pairs required (11), we need to find the minimum value of k, which represents the number of colors needed.
Since each color pair consists of two colors, the total number of colors needed is 11 * 2 = 22.
Therefore, the minimum value of k is 22.
However, we need to consider that both prints of a letter can also be colored with the same color. In this case, we can use the same color pair for both prints of a letter.
Therefore, the minimum value of k is reduced to 11.
Final Answer:
The minimum value of k that satisfies the requirement is 11, which corresponds to option 'C'.
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