Question

The present age of two brothers are in the ratio of 3 : 4. Five years back their ages were in a
ratio of 5 : 7. Find their present ages.
(Ans. 30 years and 40
yean
be in
the inhabitants of the town is 2:5. The numbers of illiterate exceeds the number of lite​

Answer 1

Question :-

The present age of two brothers are in the ratio of 3 : 4. Five years back their ages were in a ratio of 5 : 7. Find their present ages.

Answer :-

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

5 years ago :-

Age of brothers = 3x - 5 and 4x - 5

According to the question :-

➩ 3x - 5 : 4x - 5 = 5 : 7

➩ 3x - 5 / 4x - 5 = 5 / 7

➩ 7 ( 3x - 5 ) = 5 ( 4x - 5 )

➩ 21x - 35 = 20x - 25

➩ 21x - 20x = 35 - 25

➩ x = 10

Age of brothers = 10 × 3 = 30

and 10 × 4 = 40

Present Age of brothers = 30 years and 40 years

Answer 2

$\underline{\bf{\dag} \:\mathfrak{Given\: :}}$

• Present ages of two brothers are in ratio 3 : 4.

• Five years back their ages were in ratio 5 : 7.

$\underline{\bf{\dag} \:\mathfrak{Solution\: :}}$

❏ Let present ages of two brothers be 3x and4x.

$\underline{\boldsymbol{\bigstar{\;\;According \: to \: the \: Question}}}$

$\implies \sf \: \frac{3x - 5}{4x - 5} = \frac{5}{7} \\ \\ \sf \: After \: cross \: multiplication \: \\ \\ \implies \sf \: 7(3x - 5) = 5(4x - 5) \\ \\ \implies \sf21x - 35 \: = \: 20x - 25 \\ \\ \implies \sf21x - 20x \: = - 25 + 35 \\ \\ \implies \sf{x = 10}$

Therefore,

Present age of 1st Brother = 3x = 30yrs.

Present age of 2nd Brother = 4x = 40yrs.