At present, a man is 5 times older than his daughter. In 7 years, the man is 3 times as old as his daughter. What are their pres

Question

3 years ago

14

ent ages?

1 answer:

Kamila [148] · Answer 1 · 2021-11-11T13:56:59+03:00

The present age of father is 35 and daughter is 7.

Step-by-step explanation:

Let,

Age of father = x

Age of daughter = y

According to given statement;

A man is 5 times older than his daughter.

x = 5y Eqn 1

In 7 years, the man is 3 times as old as his daughter.

x+7 = 3(y+7)

$x+7=3y+21\\x=3y+21-7\\x=3y+14\ \ \ Eqn\ 2$

Putting value of x from Eqn 2 in Eqn 1

$3y+14=5y\\14=5y-3y\\14=2y\\2y=14$

Dividing both sides by 2

$\frac{2y}{2}=\frac{14}{2}\\y=7$

Putting y=7 in Eqn 1

$x=5(7)\\x=35$

The present age of father is 35 and daughter is 7.

Keywords: linear equation, substitution method

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