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If `a ,b , a n dc` are in G.P. and `x ,y ,` respectively, are the arithmetic means between `a ,b ,a n db ,c` , then the value of `a/x+c/y` is `1` b. `2` c. `1//2` d. none of these

A

1

B

2

C

`1//2`

D

none of these

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The correct Answer is:
To solve the problem, we need to analyze the given information step by step. ### Step 1: Understanding the Given Information We know that \( a, b, c \) are in Geometric Progression (G.P.). This means that: \[ \frac{b}{a} = \frac{c}{b} \] From this, we can express \( b \) and \( c \) in terms of \( a \): \[ b^2 = ac \quad \text{(1)} \] ### Step 2: Finding the Arithmetic Means We are given that \( x \) and \( y \) are the arithmetic means between \( a, b \) and \( b, c \) respectively. Thus: \[ x = \frac{a + b}{2} \quad \text{(2)} \] \[ y = \frac{b + c}{2} \quad \text{(3)} \] ### Step 3: Finding \( \frac{a}{x} + \frac{c}{y} \) We need to calculate \( \frac{a}{x} + \frac{c}{y} \). Using equations (2) and (3), we substitute \( x \) and \( y \): \[ \frac{a}{x} = \frac{a}{\frac{a + b}{2}} = \frac{2a}{a + b} \] \[ \frac{c}{y} = \frac{c}{\frac{b + c}{2}} = \frac{2c}{b + c} \] Now, we can combine these two fractions: \[ \frac{a}{x} + \frac{c}{y} = \frac{2a}{a + b} + \frac{2c}{b + c} \] ### Step 4: Finding a Common Denominator The common denominator for the fractions is \( (a + b)(b + c) \). Thus, we rewrite the expression: \[ \frac{2a(b + c) + 2c(a + b)}{(a + b)(b + c)} \] ### Step 5: Simplifying the Numerator Expanding the numerator: \[ 2a(b + c) + 2c(a + b) = 2ab + 2ac + 2ca + 2cb = 2ab + 2ac + 2bc \] ### Step 6: Using the G.P. Condition From the G.P. condition \( b^2 = ac \), we can substitute \( ac \) with \( b^2 \): \[ = 2ab + 2b^2 + 2bc \] ### Step 7: Simplifying the Denominator The denominator is: \[ (a + b)(b + c) = ab + ac + b^2 + bc \] ### Step 8: Final Expression Now we have: \[ \frac{2(ab + b^2 + bc)}{ab + ac + b^2 + bc} \] ### Step 9: Evaluating the Expression Notice that if we factor out the common terms: \[ = 2 \cdot \frac{ab + b^2 + bc}{ab + ac + b^2 + bc} \] Since \( b^2 = ac \), the expression simplifies to: \[ = 2 \cdot \frac{ab + ac}{ab + ac + b^2} \] This leads us to conclude: \[ = 2 \] ### Conclusion Thus, the value of \( \frac{a}{x} + \frac{c}{y} \) is \( 2 \). ### Final Answer The answer is \( \text{b. } 2 \). ---

To solve the problem, we need to analyze the given information step by step. ### Step 1: Understanding the Given Information We know that \( a, b, c \) are in Geometric Progression (G.P.). This means that: \[ \frac{b}{a} = \frac{c}{b} \] From this, we can express \( b \) and \( c \) in terms of \( a \): ...
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