Question

n
Five years hence, the age of Jacob will be three times that of his son. Five years
ago, Jacob's age was seven times that of his son. What are their present ages?
​

Answer 1

Answer:

Jacob is 40 years old and his son is 10 years old.

Step-by-step explanation:

Let Jacob's age be x and his son's age be y.

Now,

From 1st sentence - Five years hence, the age of Jacob will be three times that of his son.

Rewriting in equation form,

x + 5 = 3(y + 5)

=> x + 5 = 3y + 15

=> x = 3y + 15 - 5 = 3y + 10 -----------------------------------------[1]

And then,

From 2nd sentence - Five years ago, Jacob's age was seven times that of his son.

Rewriting in equation form,

x - 5 = 7(y - 5)

=> x - 5 = 7y - 35

=> x = 7y - 35 + 5 = 7y - 30 -----------------------------------------[2]

From equations 1 and 2,

3y + 10 = 7y - 30

=> 10 + 30 = 7y - 3y

=> 40 = 4y

=> y = 10

Substitute y = 10 in equation 2

x = 7y - 30 = 7 × 10 - 30 = 70 - 30 = 40

PLEASE MARK BRAINLIEST