Question 659428
This is a weird question.

Her lowest grade is possible if the other four were all 100s. The question is then what test score when averaged with four 100s gives an average of 88?

Avg=(100+100+100+100+x)/5
88=(400+x)/5
5*88=(400+x)/5 * 5
440=(400+x)*1
440=400+x
440-400=400+x-400
40=x

Substitute in in to see if the average is 88.