Answer:
Marta need to score at least 94 to receive an average of 90 or higher considering all five tests.
Explanation:
Marks received by Marta in four tests = 86, 84, 97 and 89
Let mark received in fifth test be x
We have average of five test is more than or equal to 90
So we have
[tex]\frac{86+84+97+89+x}{5} \geq 90\\ \\ 86+84+97+89+x\geq 450\\ \\ x\geq 94[/tex]
So Marta need to score at least 94 to receive an average of 90 or higher considering all five tests.