Question

If(28-x) is the mean proportion of(23-x) and (20-x) thenfind the value of x.​

Answer 1

Answer :

• x = 15.5

Explanation :

Forming an equation where (28 - x) is the mean proportion of (23 - x) and (20 - x)

$\rm \therefore \: (23 - x) :(28 - x) : :(28 - x) : (20 - x)$

Solving for ‘x’ :

$\rm \implies \: \dfrac{23 - x}{28 - x} = \dfrac{28 - x}{20 - x}$

$\rm \implies \: (23 - x)(20 - x) = (28 - x {)}^{2}$

$\rm \implies \: 560 - 20x - 28x + {x}^{2} = {(23)}^{2} - 2(x)(23) + {x}^{2}$

$\rm \implies \: 560 - 48x = 529 - 46x$

$\rm \implies \: 560 - 529 = 48x - 46x$

$\rm \implies \: 31 = 2x$

$\rm \implies \: x = \dfrac{31}{2}$

$\rm \therefore \: x = 15.5$

∴ The value of ‘x’ is 15.5

Answer 2

Answer:

23−x/28-x=19-x

i.e., (23−x)(19−x)=(28−x) ²

X²−42x+437=784−56x+x²

56x−42x=784−437

14x=347

x= 347/14

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