Paul, Joey, and Matt have to catch the train back to school at 5:00pm. They want to tour the air and space museum for 1 hour and 45 minutes, then spend 30 minutes in the gift shop and save 20 minutes to walk to the train. What time should they start the tour?

2:25pm

Step-by-step explanation:

The time given is 5pm to catch the train back to school;

Amount of time for the tour  = 1hr 45min

                                               = 105min

Amount of time at gift shop  = 30min

Amount of time to save  = 20min

 Total time = 105min + 30min + 20min  = 155min

So;

Total time  = 2hr 35min

So;

        5pm - 2hr 35min  = 2:25pm

your answer would be 10x - 1

126 maybe. sorry