Answer: The least score she can get on her next test is 455 points.
Step-by-step explanation: From the available information, her current mean score is 88%, and that was achieved from a total of 5 tests. Hence, her mean score was computed as follows;
Mean = (Summation of data)/observed data
Where the observed data is 5 and the mean is 88. Therefore the mean can now be expressed as,
88 = Summation of data/5
By cross multiplication we now have
88 x 5 = Summation of data
440 = Summation of data.
So, if she wants to raise her mean score on her next test to 91%, her least possible score would be derived as
91 = (Summation of data)/5
By cross multiplication we now have
91 x5 = Summation of data
455 = Summation of data
Therefore, on her next test, she must score at least 455 points.