Answer:
Jenny James would need to have a score of 97 out of 100 points in order to have an average of 90.
Step-by-step explanation:
Given that:
Scores of four tests
78, 89, 90 and 96
Let,
x be the score on fifth test.
Average is the sum of quantities divided by total number of quantities.
Average = 90
Average = 
Putting the values in the formula;

Hence,
Jenny James would need to have a score of 97 out of 100 points in order to have an average of 90.
This would be rational. If it were an irrational number, the integers on the right side of the decimal would go on forever.
Answer:
8.5
Step-by-step explanation:
Just eliminate the x by doing the opposite.