Math, asked by shivasinghmohan629, 1 month ago

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Five years hence, father's age will be three times the age of his son. Five years ago, father was seven times as old as his son. Find their present ages.​

Answers

Answered by CopyThat
40

Step-by-step explanation:

Given :

Five years hence, father's age will be three times the age of his son.

Five years ago, father was seven times as old as his son.

To find :

Their present ages.

Solution :

Let the present ages of the Father and the Son be x and y years.

1st condition : [Hence/Future]

=> After 5 years man’s age = x + 5  

=> After 5 years ago son’s age = y + 5  

According to the question :

=> x + 5 = 3(y + 5)

=> x + 5 = 3y + 15

=> x - 3y = 10 -- (1)

2nd condition : [Ago/Past]

=> 5 years ago man’s age = x - 5

=> 5 years ago son’s age = y - 5  

According to the question :

=> x - 5 = 7(y - 5)

=> x - 7y = -30 -- (2)

Subtracting (2) from (1) :

=> x - 7y = -30

=> x - 3y = 10

  • 4y = 40
  • y = 10

Substitute the value of y in (1) :

=> x - 3y = 10

=> x - 3(10) = 10

=> x - 30 = 10

=> x = 40

Therefore :

Father's present age = 40 years.

Son’s present age = 10 years.

...ッ

Answered by Zackary
166

Answer:

\huge \huge \bf {\: \pmb{Question}}

Five years hence, father's age will be three times the age of his son. Five years ago, father was seven times as old as his son. Find their present ages.

━━━━━━━━━━━━━━━━━━━━━

\huge \huge \bf {\: \pmb{ \blue{Solution}}}

let the present age of father be x

and, present age of son be y

According to the question :

  • Five years hence, father's age will be three times the age of his son

so, adding 5 in both sides

\dashrightarrow x + 5 = y + 5

it's says after 5 years the age of father become thrice of son's age

so multiplying with 3 in Father's age

\dashrightarrow x + 5 = ( y + 5 ) 3

\dashrightarrow x + 5 = 3y + 15

\dashrightarrow x - 3y = 10 ----(1)

Five years ago ,

Five years ago, father was seven times as old as his son

so, subtracting 5 in both sides

\dashrightarrow x - 5 = y - 5

it's says after 5 years the age of father become 7 times of son's age

so multiplying with 7 in Father's age

\dashrightarrow x - 5 = ( y - 5 ) 7

\dashrightarrow x - 5 = 7y - 35

\dashrightarrow x - 7y = - 35 + 5

\dashrightarrow x - 7y = - 30 ---(2)

Now subtracting both equations (1) & (2)

 \sf  \dashrightarrow \: x - 7y =  - 30 \\  \sf \:  \:  x  \:  - 3y = 10 \\   \:  \: \tiny( - )  \:  \:  \:  \: \:  \:  \:  \:  \:  \:  \:  \: ( + ) \:  \:  \:  \ \:  \:  \:  \:  \:  \:  \: ( - )  \\ \sf -  -  -  -  -  -  -  -  -  \\   \sf   \cancel- 4y =   \cancel- 40

\dashrightarrow 4y = 40

\dashrightarrow y = \cancel\frac{40}{4}

\dashrightarrow y = 10

therefore son's present is 10 years

to find father's present age we need to put value of y in our first equation

\dashrightarrow x - 3y = 10

\dashrightarrow x - 3(10) = 10

\dashrightarrow x - 30 = 10

\dashrightarrow x = 10 + 30

\dashrightarrow x = 40

therefore, father's present age is 40 years

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