d 2(y+2) Ilcole noticed that her Physics average was not as high as she thought. Her grades are 9,88,89,95 and 89. What grade must she score on her last test in order to get an verage of 90 for the course?

To find the grade Ilcole needs on her last test to achieve an average of 90 for the course, we can use the formula for calculating the average:

average = (sum of all grades) / (number of grades)

In this case, we know that Ilcole's grades are 9, 88, 89, 95, and 89. We can substitute these values into the formula:

90 = (9 + 88 + 89 + 95 + x) / 5

To solve for x, we can multiply both sides of the equation by 5:

450 = 281 + x

Subtracting 281 from both sides gives us:

169 = x

Therefore, Ilcole needs to score a 169 on her last test in order to achieve an average of 90 for the course.