Caleb scored the following on his first four tests: 78, 84, 88, and 82. What is the least grade he can receive on his next test to have an average of 85 for the five tests?
a.66
b.83
c.93
d.100
5*85=78+84+88+82+N
solve for N
83
93
To find the answer to this question, we need to consider the average of the five tests. The average score is calculated by adding up all the individual scores and then dividing the sum by the number of tests. In this case, we know that the desired average score is 85 and that Caleb has already taken four tests with scores of 78, 84, 88, and 82.
So, let's calculate the current sum of the scores: 78 + 84 + 88 + 82 = 332.
To find the least grade Caleb can receive on his next test and still have an average of 85, we can use the average formula:
(332 + x) / 5 = 85.
Here, x represents the score Caleb gets on his next test. Solving for x, we can start by multiplying both sides of the equation by 5:
332 + x = 85 * 5.
Then, simplify the equation:
332 + x = 425.
Next, subtract 332 from both sides of the equation:
x = 425 - 332.
Finally, calculate the result:
x = 93.
Therefore, Caleb needs to score at least 93 on his next test to have an average of 85 for the five tests. Thus, the correct answer is c. 93.