Final answer:
By setting up a system of equations using the given information, we find that John is currently 18 years old.
Step-by-step explanation:
To find John's current age, let's set up a system of equations based on the information provided. Let J represent John's age now, and S represent Sarah's age now.
We are given that the sum of the ages of John and Sarah is 26, so our first equation is:
J + S = 26
Five years ago, John was three times as old as Sarah. This gives us our second equation:
J - 5 = 3(S - 5)
Rearrange the second equation to solve for J:
J = 3S - 10 + 5
J = 3S - 5
Now we can substitute the value of J from the first equation:
(26 - S) = 3S - 5
Adding 5 to both sides and then adding S to both sides gives us:
31 = 4S
Dividing both sides by 4 gives us:
S = 7.75
Since ages are typically whole numbers, let's round Sarah's age to the nearest whole number, which is 8. Now we substitute the value of S back into the first equation to find J:
J = 26 - 8
J = 18
So, John is currently 18 years old.