by Sahana
(Kolkata)
Arvind is eight year older than his sister. in three year, he will be twice as old as his sister. how old was 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




Jan 18, 19 10:53 AM
This overtime calculator will help you figure out how much money earned for working overtime
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.
Jan 18, 19 10:53 AM
This overtime calculator will help you figure out how much money earned for working overtime
Our Top Pages
Formula for percentage
Compatible numbers
Basic math test
Basic math formulas
Types of angles
Math problem solver
Algebra word problems
Surface area of a cube
Finding the average
Scale drawings
Everything you need to prepare for an important exam!
K12 tests, GED math test, basic math tests, geometry tests, algebra tests.
Real Life Math Skills
Learn about investing money, budgeting your money, paying taxes, mortgage loans, and even the math involved in playing baseball.