Answer:
Each one will have saved $25 after 1 week
Step-by-step explanation:
If y is the amount saved and x is the number of weeks, we get that the system of equations is
y = 5 + 20x
y = 8 + 17x
Because the amount saved by Hunter will be equal to the $5 that he has added to $20 times the number of weeks and the amount saved by his sister will be equal to $8 added to $17 per week.
Then, to solve the system substitude the first equation on the second
y = 8 + 17x
5 + 20x = 8 + 17x
Solving for x, we get:
5 + 20x - 17x = 8 + 17x - 17x
5 + 3x = 8
5 + 3x - 5 = 8 - 5
3x = 3
3x/3 = 3/3
x = 1
Finally, the value of y is
y = 5 + 20x
y = 5 + 20(1)
y = 25
Therefore, each one will have saved $25 after 1 week.