How would you find the fourth number in this set, 23, 29, 27 when doing five number summary?

Question

This is an algebra question demonstrating the 5 number summary and box plots. The complete problem: Stu had a mean score of 25.5 on four 30 point papers in English. He remembers three scores: 23, 29, 27. Estimate the fourth score without actually calculating it. Then check estimate by calculating the 4th score. Now, what is the five number summary for this situation? Does it make sense to have a five number summary for this data set? Why or Why not?

Answer 1

The question states "Stu had a mean score of 25.5 on four 30 point papers in English. He remembers three scores: 23, 29, 27." What does that mean? That means: 23 +29 + 27 + (4th score) = 4*25.5 = 102. Hence the 4th score is 102 - (23+29+27) = 23