Question

10. Junhao's sister is 5 years old. She is 36 years younger than their mother. In how many years' time will their mother's age be 4 times her age?
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Answer 1

Answer:

Junhao's age is 5.

Then, her mother's age = 36 + 5 = 41

Let after x years, her mother will be 4 times her age.

After x years:

Age of Junhao = 5 + x

Age of her mother = 41 + x

According to question,

⇒ 41 + x = 4(5 + x)

⇒ 41 + x = 20 + 4x

⇒ 4x - x = 41 - 20

⇒ 3x = 21

⇒ x = 7 years

Let's verify it:-

Junhao's age will be 5 + 7 = 12.

Her mother's age will be 41 + 7 = 48.

Her mother's age is 4 times of Junhao (12 × 4 = 48).

Answer 2

Junhao's sister age is 5

THEN,

Her mother's age= 36+5=41

Let after X years , Her mother will be 4 times her age.

After X years:

Age of Junhao= 5+X

Age of her mother: 41+X

According to the question,

=> 41+X= 4(5+X)

=> 41+X= 20+4x

=> 4x-x= 41-20

=> 3x. = 21

=> x. = 21/3

=> x = 7

Let's verify it :

Junhao's age will be = 5+7= 12Her mothers age will be = 41+7= 48

Her mothers age is 4 times of Junhao (12×7= 48).

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