Question

1. Sarah's age is twice that of her sister. When you add Sarah's age to her sister's age, you get 33. How old is

each sister?
(a) Write an equation that represents the situation. Explain any variable used.
(b) Solve the equation from Part (a). Show your work. State your solution as a complete sentence.

Answer 1

x+2x=33

3x=33

x=11

Sara's sisiter is 11

Sarah is (11 times 2) 22

Answer 2

For this case we have:

x: Variable that represents Sarah's age

y: Variable that represents the age of your sister

So:

`x = 2y\\y + x = 33`

Substituting the first equation in the second we have:

`y + 2y = 33\\3y = 33\\y = \frac {33} {3}\\y = 11`

So, Sarah's sister is 11 years old.

`x = 2y = 2 (11) = 22`

Sarah is 22 years old.

Answer:

`y + 2y = 33` Where "y" is the age of Sarah's sister

Sarah's sister is 11 years old and Sarah is 22 years old.