Answer:
3/10
Explanation:
The total distance to Derek's aunt's house will be 10/10 of the distance. If 3/10 of the distance is traveled on Saturday, then ...
10/10 -3/10 = 7/10
of the total distance remains to be traveled.
3/7 of that remaining distance is traveled on Sunday. The fraction of the total distance that represents is ...
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3/10 of the total distance to his aunt's house was traveled on Sunday.