Question

five year hence , the age of Jacob will be 3 times that of his son. five years ago,Jacob's age was seven times that of his son. what are their present ages??
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Answer 1

Answers:

hi

Let son's age be x.

Son's age after 5 years.

x + 5

So,

According to given condition ,

Jacobs age = 3(x+5) = 3x+15

His present age = 3x +15 - 5

= 3x+10 ....................... (1)

Five years ago....

Son's age = x - 5

According to the given condition,

Jacobs age = 7(x - 5)

Jacobs age = 7x - 35

His present age = 7x - 35 + 5 =

7x - 30 . . . . . . . .. . . . . . (2)

3x+10=7x-30

10+30=7x-3x

40=4x

X=10

So,

His sons present age is 10years.

Present age of Jacob=

3x + 10 ...............................from(1)

3(10)+10 = 30 + 10 = 40years.

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Final Answer :

The present ages of Jacob and Son are 40years and 10years.

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Answer 2

$\bf{\underline{\green{QuEsTiOn:-}}}$

✓✓five year hence , the age of Jacob will be 3 times that of his son. five years ago,Jacob's age was seven times that of his son. what are their present ages?

$\bf{\underline{\pink{SoLuTiOn:-}}}$

let the Jacob's present age be x years.

And his son's present age be y years.

Five year hence,

Jacob's age will be x + 5 years.

and his son's age will be y + 5 years.

Also, five years hence,Jacob age will be 3 times that of his son.

Therefore,

$\bf\:x+5=3(y+5)$

$\bf\:x+5=3y+15$

$\bf\:x=3y+10.................(i)$

Five years ago, Jacob's age will be x - 5 years.

and his son's age will be y - 5 years.

Also,five years ago Jacob's age will be seven times that of his son.

therefore,

$\bf\:x-5=7(y-5)$

$\bf\:x-5=7y-35$

$\bf\:x=7y-30...............(ii)$

equating equations (i) and (ii) ,we get

$\bf\:3y+10=7y-30$

$\bf\:10+30=7y-3y$

$\bf\:40=4y$

$\bf\therefore\:4y=40$

$\bf\:y=\dfrac{40}{4}$

$\bf\:y=10$

then,

$\bf\:x=40$

so, present age of Jacob's = 40 years.

and present age of his son's = 10 years.