Answer:
d = 510 km
Explanation:
She travelled the final 4 hours at a constant speed of 60 km/h.
distance = speed × time
distance = 60 km/h × 4 hours
distance = 240 km for the last 4 hours
She already had travelled 270 km in the first 3 hours.
d = total distance = 270 km + 240 km = 510 km
Answer: d = 510 km