Charla wants to cover a certain rectangular area of her driveway with a picture using chalk. If she completes 2/3 if the area in 1/2hour, how long will it take her to complete the entire picture?

To determine how long it will take Charla to complete the entire picture on her driveway, we can first find out how long it takes her to complete \( \frac{2}{3} \) of the area.

Charla completes \( \frac{2}{3} \) of the area in \( \frac{1}{2} \) hour.

To find out how long it will take her to complete the entire area (which is \( 1 \) whole), we can set up a proportion. If \( \frac{2}{3} \) of the area takes \( \frac{1}{2} \) hour, then we can calculate the time \( T \) for the entire area as follows:

\[
T = \frac{1 \text{ (whole area)}}{\frac{2}{3} \text{ (completed area)}} \times \frac{1}{2} \text{ (time taken)}
\]

To simplify this, we can calculate the reciprocal of \( \frac{2}{3} \):

\[
\frac{1}{\frac{2}{3}} = \frac{3}{2}
\]

Now substituting this back into the equation for \( T \):

\[
T = \frac{3}{2} \times \frac{1}{2}
\]

Multiplying these together:

\[
T = \frac{3 \times 1}{2 \times 2} = \frac{3}{4} \text{ hours}
\]

Now, converting \( \frac{3}{4} \) hours into minutes (since \( 1 \) hour is \( 60 \) minutes):

\[
\frac{3}{4} \text{ hours} = \frac{3 \times 60}{4} = 45 \text{ minutes}
\]

Thus, it will take Charla \( \boxed{45} \) minutes to complete the entire picture on her driveway.