Answer :
According to the information given, we have that:
a) The system of equations is given by: x + y = 850, 0.5x + 0.75y = 500.
b) You has saved $550 and your sister has saved $300.
What is a system of equations?
A system of equations is when two or more variables are related, and equations are built to find the values of each variable.
In this problem, the variables are:
- Variable x: The amount you have saved up.
- Variable y: The amount your sister has saved up.
Item a:
Together you have $850 saved up, hence:
x + y = 850.
You contribute 50% of your savings and your sister contributes 75% of hers toward the $500 cost, hence:
0.5x + 0.75y = 500.
Item b:
From the first equation, we have that:
x = 850 - y
Replacing on the second:
0.5(850 - y) + 0.75y = 500
0.25y = 75
y = 75/0.25
y = 300
x = 850 - y = 550.
You has saved $550 and your sister has saved $300.
More can be learned about a system of equations at https://brainly.com/question/24342899
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