Question

Pamela's age is two times Jiri's age. The sum of their ages is 63 . What is Jiri's age?

Answer 1

2x + x = 63
3x = 63
x = 21
2x = 43
Jiri is 21

Answer 2

Let x be Pamela's age, and y Jiri's age.
"Pamela's age is 2 times Jiri's age" can be represented by x = 2y
"The sum of their ages is 63" So x + y = 63

We can now create a system of 2 equations:
x = 2y (1)
x + y = 63 (2)

Let's take the algebraic value of x from equation (1) and replace it in equation (2):
x + y = 2y + y = 3y
So 3y = 63
Divide both sides by 3 to isolate y on a side and its value on the other:
(3y)/3 = 63/3
y = 21

So Jiri's age is 21 years old.

Hope this Helps! :)