Answer:
11:10 am.
Explanation:
The first thing I'm going to do is to add all the given time together
Total time = time spent at Willis tower + time spent at Navy Pier + time spent shopping
Total time = 1 HR and 10 minutes + 3 HR and 10 minutes + 1 hour and 15 minutes
Total time = (1 + 3 + 1) hr + (10 + 10 + 15) minutes
Total time = 5 hours + 35 minutes
The question doesn't make mention of how long they spent making the journey so, I'm assuming they spent 35 minutes driving around from Willis to the Pier and finally while shopping
Time = total time + time spent driving
Time = 5 hours 35 minutes + 35 minutes
Time = 6 hours and 10 minutes
Now, this time we've calculated, is what we're going to subtract from the dinner time to get our final answer
Needed time = dinner time - time
Needed time = 5:10 pm - 6:10
Needed time = 17:10 - 6:10
Needed time = 11:10
This means that they ought to start their tour by 11:10 am, so that they can meet their dinner