Let G be the geometric mean of two positive n | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) $G = \sqrt{ab}$$M = \frac{\frac{1}{a} + \frac{1}{b}}{2} = \frac{a + b}{2ab}$Given that $\frac{1}{M} : G = 4 : 5$,we have $\frac{2ab}{(a + b)\sqrt{

Vedclass · Accepted Answer

$1:4$

Vedclass · Answer

(A) $G = \sqrt{ab}$$M = \frac{\frac{1}{a} + \frac{1}{b}}{2} = \frac{a + b}{2ab}$Given that $\frac{1}{M} : G = 4 : 5$,we have $\frac{2ab}{(a + b)\sqrt{ab}} = \frac{4}{5}$$\Rightarrow \frac{a + b}{2\sqrt{ab}} = \frac{5}{4}$Using Componendo and Dividendo:$\frac{a + b + 2\sqrt{ab}}{a + b - 2\sqrt{ab}} = \frac{5 + 4}{5 - 4}$$\Rightarrow \frac{(\sqrt{a} + \sqrt{b})^2}{(\sqrt{a} - \sqrt{b})^2} = 9$$\Rightarrow \frac{\sqrt{a} + \sqrt{b}}{\sqrt{a} - \sqrt{b}} = 3$ (assuming $a > b$ for positive ratio)$\Rightarrow \sqrt{a} + \sqrt{b} = 3\sqrt{a} - 3\sqrt{b}$$\Rightarrow 4\sqrt{b} = 2\sqrt{a}$ $\Rightarrow \sqrt{\frac{a}{b}} = 2$ $\Rightarrow \frac{a}{b} = 4$Since the ratio $a:b$ can be $1:4$ or $4:1$,and $1:4$ is given in the options,the correct answer is $1:4$.

Let $G$ be the geometric mean of two positive numbers $a$ and $b,$ and $M$ be the arithmetic mean of $\frac{1}{a}$ and $\frac{1}{b}.$ If $\frac{1}{M} : G$ is $4:5,$ then $a:b$ can be

Similar Questions

If the ratio of two numbers is $9:1$,then the ratio of their geometric mean to their harmonic mean is

If the ratio of the harmonic mean to the geometric mean of two positive numbers $a$ and $b$ $(a > b)$ is $4 : 5$,then $a : b = \dots$ (in $: 1$)

What is the minimum value of the sum of the real numbers $a^{-5}, a^{-4}, 3a^{-3}, 1, a^8$,and $a^{10}$ where $a > 0$?

Three positive numbers form an increasing $G.P.$ If the middle term in this $G.P.$ is doubled,the new numbers are in $A.P.$ Then the common ratio of the $G.P.$ is:

$A$ car completes the first half of its journey with a velocity $v_1$ and the rest half with a velocity $v_2$. Then the average velocity of the car for the whole journey is

Vedclass Test Series

Exam Paper Generator

Online Exam Module