The driver's speed goes up by 3 km/hr every hour, and he covers 30 km in the first hour, so the distance covered each hour forms a sequence increasing by 3 km/hr. The total distance over 7 hours is the sum of this sequence, which we can check against each option using the average-times-terms method.
Since the sequence of hourly distances is evenly spaced, its average equals the 4th (middle) term, 39 km, and 7 hours at that average gives 273 km.
Therefore, the correct answer is 273 km.
The distances covered each hour form an arithmetic sequence with first term \( a = 30 \) km and common difference \( d = 3 \) km, since the speed rises by 3 km/hr every hour. Using the sum formula for an arithmetic series, \( S_n = \frac{n}{2} \left[ 2a + (n - 1)d \right] \), with \( n = 7 \): \[ S_7 = \frac{7}{2} \left[ 2(30) + (6)(3) \right] = \frac{7}{2} \left[ 60 + 18 \right] = \frac{7}{2} \times 78 = 273 \] Let's check each option by working out what common difference it would actually require, keeping \( a = 30 \) and \( n = 7 \) fixed.
Only a common difference of exactly 3 km/hr, as stated in the question, produces a total distance of 273 km through the arithmetic series sum formula.
Therefore, the correct answer is 273 km.