Math problem about age

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

Add 10 to both sides

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.


Comments for Math problem about age

Average Rating starstarstarstarstar

Click here to add your own comments

Jun 18, 2018
Rating
starstarstarstarstar
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

Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Algebra word problems.

Recent Articles

  1. Quadratic Formula: Easy To Follow Steps

    Jan 26, 23 11:44 AM

    Quadratic formula
    Learn about the quadratic formula, the discriminant, important definitions related to the formula, and applications.

    Read More

  2. Area Formula - List of Important Formulas

    Jan 25, 23 05:54 AM

    Frequently used area formulas
    What is the area formula for a two-dimensional figure? Here is a list of the ones that you must know!

    Read More

Tough algebra word problems

100 Tough Algebra Word Problems.

If you can solve these problems with no help, you must be a genius!

Math quizzes

 Recommended

Math vocabulary quizzes