Answer:
It will take Rosa 5 and a half (5.5) weeks to have the same amount of money in both accounts.
Explanation:
For this problem, we will have to set two expressions equal to each other. The first expression will represent Rosa's saving account, which already has $117 in it. Every week (
), she adds $21 to her savings account:
![21x+117](https://img.qammunity.org/2021/formulas/mathematics/high-school/m5qgjdqr5tmbco0rx9aeol6m3bk3u8odkl.png)
The second expression will represent Rosa's checking account. Rosa's checking account already has $95 in it. Every week (
), she adds $25 to her checking account:
![25x+95](https://img.qammunity.org/2021/formulas/mathematics/high-school/m1qc6wrmndwims2iuelyrxwuqcdnqu81az.png)
Now that we have our two expressions, set them equal to each other. This is our equation that will be used to find the number of weeks (
) it takes until Rosha has the same amount of money in both accounts:
![21x+117=25x+95](https://img.qammunity.org/2021/formulas/mathematics/high-school/i9wpo1mmqfva36y42qoiq69f3hvopiojvk.png)
Subtract
from both sides of the equation:
![117=4x+95](https://img.qammunity.org/2021/formulas/mathematics/high-school/pwqncluw27ofwomixxwwf2dfwbc4p9sm6t.png)
Subtract
from both sides of the equation:
![22=4x](https://img.qammunity.org/2021/formulas/mathematics/high-school/tv9nm1hkkxnhn00iz8a6ly40xt7xjdaky3.png)
Divide both sides of the equation by the coefficient of
, which is
:
![5.5=x](https://img.qammunity.org/2021/formulas/mathematics/high-school/6zoxprab2i5ynlqptzlapn4fgdwtkjnil7.png)
![x=5.5](https://img.qammunity.org/2021/formulas/mathematics/middle-school/x4mtblm15f4479lbwmxnzm0smdc4ct9mrv.png)
So it will take five and a half weeks for her accounts to have the same amount of money.
_
Check your work by substituting
into the initial equation:
![21(5.5)+117=25(5.5)+95](https://img.qammunity.org/2021/formulas/mathematics/high-school/r216z09lmv65197mitaddtrd5jcopmi9nb.png)
![115.5+117=137.5+95](https://img.qammunity.org/2021/formulas/mathematics/high-school/xsdpqeglyn4x4r9r45ki4yd345pl69pcyl.png)
![232.5=232.5](https://img.qammunity.org/2021/formulas/mathematics/high-school/p2qsj2qq8x4p37h7sh2eugi0oy0s4c497b.png)
Since the accounts have the same amount, the answer is correct!