Wanda wants to have a test average of 90 her four science tests. On the first three tests, she got scores of 84, 96, and 85. What does she need on her last test to reach her goal?
84 + 96 + 85 = 265
400 * 0.9 = 360
360 - 265 = ?
84+96+85 + x = 4*90
95
To find out what Wanda needs on her last test to reach her goal, we can use the formula for average:
Average = (Sum of all scores) / (Number of scores)
In this case, Wanda wants to have an average of 90 for her four science tests. Let's call the score she needs on the last test "x". We can set up the equation as follows:
(84 + 96 + 85 + x) / 4 = 90
To solve this equation, we need to isolate the variable "x" on one side. We can do this by multiplying both sides of the equation by 4:
84 + 96 + 85 + x = 90 * 4
Simplifying the equation:
265 + x = 360
Now, we can isolate "x" by subtracting 265 from both sides:
x = 360 - 265
x = 95
Therefore, Wanda needs a score of 95 on her last test to reach her goal of a 90 average.