by Sahana
(Kolkata)

Arvind is eight years older than his sister. In three years, he will be twice as old as his sister. how old are they are now?

Solution

Let x be a Arvind's age.

Let x - 8 be his sister's age.

In 3 years, Arvind's age will be x + 3

In 3 years, the sister's age will be x - 8 + 3 = x - 5

In 3 years, Arvind is twice as old as his sister.

x + 3 = 2 × (x - 5)

x + 3 = 2x - 10

2x - 10 = x + 3

Subtract x from both sides.

2x - x - 10 = x - x + 3

2x - x - 10 = 3

2x - x - 10 + 10 = 3 + 10

2x - x = 3 + 10

x = 13

Arvind's age is 13

His sister's age is 13 - 8 = 5.

In 3 years, Arvind's will be 16 and the sister will be 8.

16 is twice as big as 8.

Average Rating     Jun 18, 2018 Rating     Arvin and her Sister NEW by: Anonymous Arvin is 8 years older than her sister why will you reduce the age of her sister it should be plus 8 to be equal to Arvin's Age the equation should be Arvin=Sister+8

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