Solution
- Let the amount you have saved up be x and the amount your sister has saved up be y.
- We are told that together, you both have $850 saved up. This implies that

- We are also told that you contribute 50% of your savings. That is,

- We are also told that your sister contributes 75% of hers. That is,

- Since your contributions is towards buying the $500 Playstation, we can say:

Question 1:
- Thus, the system of equations is

Question 2:
- To solve the question using elimination, we need to make the coefficients of either x or y the same for both equations. We can simply do this by multiplying Equation 1 by 0.75 or 0.5 to make the coefficients of y or x respectively, be the same in both equations

- The solution to the system of equations is: x = 550, y = 300
Question 3:
- Elimination is a good way to solve the question because the coefficients of Equation 1 are both 1. Thus, we can easily create a new Equation that can have its x or y-term eliminated when added or subtracted to or from another equation.