Answer:
Karina must score atleast 92 on the fifth test to get a average of atleast 84.
Step-by-step explanation:
We are given the following in the question:
84, 86, 90, 68
We want the average score to be atleast 84.
Let x be the score on fifth test.
Formula:
[tex]Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}[/tex]
Thus, we can write the equation:
[tex]\dfrac{84+86+90+68+x}{5}\geq 84\\\\\Rightarrow 84+86+90+68+x \geq 420\\\Rightarrow 328+x \geq 420\\\Rightarrow x \geq 92[/tex]
Thus, Karina must score atleast 92 on the fifth test to get a average of atleast 84.
