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QJEEM23Ma91f2: JEE Main 2023 Mathematics - Class 11 JEEM23Ma91f2 Solution: Let and be positive real numbers such that . If the maximum…

Let a,b,ca, b, c and dd be positive real numbers such that a+b+c+d=11a+b+c+d=11 . If the maximum value of a5b3c2da^{5} b^{3} c^{2} d is 3750β3750 \beta , then the value of β\beta is

Multiple Choice Options

  • A 110
  • B 108
  • C 90
  • D 55

Step-by-Step Verified Solution

Given that a+b+c+d=11a+b+c+d=11 and the maximum value of a5b3c2da^5 b^3 c^2 d is 3750β3750\beta , you assumed the numbers to be a5,a5,a5,a5,a5,b3,b3,b3,c2,c2,d\frac{a}{5}, \frac{a}{5}, \frac{a}{5}, \frac{a}{5}, \frac{a}{5}, \frac{b}{3}, \frac{b}{3}, \frac{b}{3}, \frac{c}{2}, \frac{c}{2}, d .

Applying the AM-GM inequality:

a5+a5+a5+a5+a5+b3+b3+b3+c2+c2+d11≥((a5b3c2d)5533221)111\frac{\frac{a}{5}+\frac{a}{5}+\frac{a}{5}+\frac{a}{5}+\frac{a}{5}+\frac{b}{3}+\frac{b}{3}+\frac{b}{3}+\frac{c}{2}+\frac{c}{2}+d}{11} \geq\left(\frac{\left(a^5 b^3 c^2 d\right)}{5^5 3^3 2^2 1}\right)^{\frac{1}{11}}

Since a+b+c+d=11a+b+c+d=11 , we have:

1≥((a5b3c2d)5533221)1111 \geq\left(\frac{\left(a^5 b^3 c^2 d\right)}{5^5 3^3 2^2 1}\right)^{\frac{1}{11}}

Now, raising both sides to the power of 11:

111≥a5b3c2d55332211^{11} \geq \frac{a^5 b^3 c^2 d}{5^5 3^3 2^2 1}

From the given information, we know that a5b3c2d≥3750βa^5 b^3 c^2 d \geq 3750\beta :

553322≥3750β5^5 3^3 2^2 \geq 3750\beta

Now, we can solve for β\beta :

β≤13750⋅553322\beta \leq \frac{1}{3750} \cdot 5^5 3^3 2^2

Since we are looking for the maximum value of β\beta , we take the equality case:

β=13750⋅553322\beta = \frac{1}{3750} \cdot 5^5 3^3 2^2

Calculating the value, we find that:

β=90\beta = 90

So, the value of β\beta is 90.

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