To solve this problem, we need to determine how long it takes Charla to complete 1/3 of the area (since she has already completed 2/3 in 1/2 hour).
To do this, we can set up a proportion between the completed area and the time taken:
2/3 area / 1/2 hour = 1/3 area / t hour
Cross-multiplying, we get:
(2/3) * t = (1/3) * (1/2)
Simplifying further, we have:
2t/3 = 1/6
To find the value of t, we can multiply both sides of the equation by 3/2:
(2t/3) * (3/2) = (1/6) * (3/2)
This gives us:
t = 1/4
Therefore, it will take Charla 1/4 of an hour or 15 minutes to complete the remaining 1/3 of the area.