Answer:
Sally is currently 4 years old.
Step-by-step explanation:
<em>Kaden is 18 years older than Sally now. In 5 years, Kaden will be 3 times as old as Sally. How old is Sally now?</em>
<em />
Let Kaden's current age be
and Sally's current age be
. We can write the following algebraic equation using the fact that Kaden is currently 18 years older than Sally:
![k=s+18](https://tex.z-dn.net/?f=k%3Ds%2B18)
Next, we will use the fact that in 5 years, Kaden will be 3 times as old as Sally. If Kaden and Sally's current ages are
and
respectively, then their ages in 5 years will be
and
respectively. Therefore, we have:
![k+5=3(s+5)](https://tex.z-dn.net/?f=k%2B5%3D3%28s%2B5%29)
We have two equations with two variables. To solve for either variable, we need to create an equation with only one variable. Therefore, let's substitute the first equation into the second:
![(s+18)+5=3(s+5)](https://tex.z-dn.net/?f=%28s%2B18%29%2B5%3D3%28s%2B5%29)
Distribute and combine like terms:
![s+18+5=3s+15,\\s+23=3s+15](https://tex.z-dn.net/?f=s%2B18%2B5%3D3s%2B15%2C%5C%5Cs%2B23%3D3s%2B15)
Subtract
from both sides, then subtract 15 from both sides:
![8=2s](https://tex.z-dn.net/?f=8%3D2s)
Divide both sides by 2:
Therefore, Sally is currently 4 years old.