Question

the age of Rohan and Rohit are in the ratio 5 ratio 7. 4 years later there is will be in the ratio 3 ratio 4 find their age​

Answer 1

$\Large{\underline{\underline{\mathfrak{\red{\bf{Solution}}}}}}$

$\Large{\underline{\mathfrak{\orange{\bf{Given}}}}}$

• The age of Rohan and Rohit are in the ratio 5 :7
• 4 years later there is will be in the ratio 3 : 4

$\Large{\underline{\underline{\mathfrak{\red{\bf{Explanation}}}}}}$

Let,

• Present Age of Rohan = x years
• Present Age of Rohit = y years

A/C to question,

(The age of Rohan and Rohit are in the ratio 5 :7)

➥ x : y = 5 :7

➥x/y = 5/7

➥ 7x - 5y = 0_________(1)

Again,

(4 years later there is will be in the ratio 3 : 4)

➥ (x+4):(y+4) = 3:4

➥ (x+4)/(y+4) = 3/4

➥ 4 * (x+4) = 3 * (y+4)

➥ 4x - 3y = 12 - 16

➥ 4x - 3y = -4 __________(2)

Multiply by 3 in equ(1) & 5 in equ(2)

• 21x - 15y = 0
• 20x - 15y = -20

_________________Sub. its

➥ 21x - 20x = 20

➥ x = 20

Keep value of x in equ(1)

➥ 7 × 20 - 5y = 0

➥ 5y = 140

➥y = 140/5

➥y = 28

$\Large{\underline{\underline{\mathfrak{\red{\bf{Hence}}}}}}$

• Present Age of Rohan (x) = 20 years
• Present Age of Rohit(y) = 28 years

__________________

Answer 2

$\mathfrak{\huge{\red{\underline{\underline{ANSWER:-}}}}}$

Let,

Present Age of Rohan = x years

Present Age of Rohit = y years

A/C to question,

(The age of Rohan and Rohit are in the ratio 5 :7)

➥ x : y = 5 :7

➥x/y = 5/7

➥ 7x - 5y = 0_________(1)

Again,

(4 years later there is will be in the ratio 3 : 4)

➥ (x+4):(y+4) = 3:4

➥ (x+4)/(y+4) = 3/4

➥ 4 * (x+4) = 3 * (y+4)

➥ 4x - 3y = 12 - 16

➥ 4x - 3y = -4 __________(2)

Multiply by 3 in equ(1) & 5 in equ(2)

21x - 15y = 0

20x - 15y = -20

_________________Sub. its

➥ 21x - 20x = 20

➥ x = 20

Keep value of x in equ(1)

➥ 7 × 20 - 5y = 0

➥ 5y = 140

➥y = 140/5

➥y = 28

Present Age of Rohan (x) = 20 years

Present Age of Rohit(y) = 28 years