Question

the ages of hari and harry are in the ratio of 5:7 four years from now the ratio of their ages will be 3:4 find their present ages​

Answer 1

${\huge {\underline {\underline {\mathfrak {\red {Ånswer}}}}}}$

Let the age of hari = 5x

Let the age of harry = 7x

ATQ,

=$\displaystyle\frac {5x+4}{7x+4}=\displaystyle\frac {3}{4}$

= 4 (5x+4) = 3(7x+4)

= 20x + 16 = 21x + 12

= +16 - 12 = 21x - 20x

= 4 = x

Age of hari = 5x = 5 × 4 = 20

Age of harry = 7x = 7 × 4 = 28

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Answer 2

$\boxed{\red{\mathbb Answer}}$

Given:

Ages of Hari and Harry are in the ratio = 5:7

Ratio of ages of Hari and Harry after 4 years = 3:4

To Find:

The present age of Hari.

The present age of Harry.

Solution:

Given that,

Ages of Hari and Harry are in the ratio = 5:7

Ratio of ages of Hari and Harry after 4 years = 3:4

According the question,

$\tt\dfrac{Age \: of \: Hari}{Age \: of \: Harry} =\dfrac{5}{7}$

Let Hari's age be 5x years and Harry's be 7x years.

Then after four years,

Hari's age = $\tt (5x+4)(5x+4)$ years

Harry's age = $\tt (7x+4)(7x+4)$ years

It's given that,

Ratio of ages of Hari and Harry after 4 years = 3:4

Then,

$\tt \dfrac{Hari's \: age \: after \: 4 \: years}{Harry's \: age \: after \: 4 \: years}=\dfrac{3}{4}$

$\tt \longrightarrow \dfrac{5x+4}{7x+4} =\dfrac{3}{4}$

$\tt 4(5x+4)=3(7x+4)$

$\tt 20x+16=21x+12$

$\tt 16-12=21x-20x$

$\tt x=4$

Therefore,

Present age of Hari = $\tt 5x=5 \times 4=20$ years

Present age of Harry = $\tt 7x=7 \times 4=28$ years

Hence the present age of Hari is 20 years and the present age of Harry is 28 years.