Question

3./टो भाइयों की वर्तमान आयु 3:4 के अनुपात में है। पाँच वर्ष पहले उनकी आयु 5:7 के अनुपात में थी। उनकी वर्तमान आयु बताओ।
The present age of two brothers are in the ratio of 3:4. Five years back their ages were in the ratio of5:7.
Find their present ages.
[Ans. 30 वर्ष तथा 40 वर्ष)
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Answer 1

Answer:

The present ages of two brothers are 30 years and 40 years.

Step-by-step explanation:

Let,

• The present age of One brother = 3x

• The present age of Second brother = 4x

★ Five years ago,

The age of One brother = 3x - 5

The age of Second brother = 4x - 5

Five years ago their ages were in the ratio = 5 : 7

According to question:

⇒ $\frac{3x \: - \: 5}{4x \: - \: 5} \: = \: \frac{5}{7}$

⇒ 7 (3x - 5) = 5 (4x - 5)

⇒ 21x - 35 = 20x - 25

⇒ 21x - 20x = -25 + 35

⇒ 1x = 10

⇒ x = 10

★ The present age of One brother = 3x

⇒ 3 (10)

⇒ 3 × 10

⇒ 30

The present age of One brother = 30 years

★ The present age of Second brother = 4x

⇒ 4 (10)

⇒ 4 × 10

⇒ 40

The present age of Second brother = 40 years

Therefore,

The present ages of two brothers are 30 years and 40 years.

Answer 2

Let the present age of two brothers be 3x and 4x .

Five years ago their ages will become ( 3x - 5 ) and ( 4x - 5 ) respectively .

Five years ago their ages were in the ratio = 5 : 7

$\longrightarrow \frac{3x - 5}{4x - y} =\frac{5}{7}$

$\longrightarrow 7 (3x - 5) = 5 (4x - 5)$

$\longrightarrow 21x - 35 = 20x - 25$

$\longrightarrow 21x - 20x = 35 - 25$

$\longrightarrow\underline { x = 10}$

The present age of two brothers are 30 years and 40 years .

HOPE IT HELPS U ............