We can use the formula:
distance = rate × time
where distance is the total length of the road built, rate is the speed at which the road was built, and time is the number of weeks it took to build the road.
Substituting the given values, we get:
7.68 kilometers = 6 kilometers/week × time
To solve for time, we can divide both sides of the equation by 6 kilometers/week:
7.68 kilometers ÷ 6 kilometers/week = time
Simplifying the left-hand side, we get:
1.28 weeks = time
Therefore, it took the construction crew approximately 1.28 weeks to build the road.