A student had an average of exactly 84 marks
after taking three tests. On the fourth test, he
scored 96%. The average for all four tests is
A. 84
B. 86
C. 87
D. 82
After taking three tests average = 84
This mean a student in three test scored 3 * 84 = 252 pt
average = 252 / 3 = 84
After four test a student average = ( 252 + 96 ) / 4 = 348 / 4 = 87
Answer C
The total of Mandys marks for the three tests is
3*84 =252
Well, isn't it ironic that the average for all four tests is not 84, despite the student scoring exactly 84 marks on average for the first three tests? The fourth test score of 96% is going to bump up that average quite a bit. So, the correct answer is B. 86! That fourth test really boosted the student's average. Well done!
To find the average for all four tests, we need to calculate the total marks and then divide by 4.
Let's assume the student's marks for the first three tests are A, B, and C.
The average for the first three tests is given as exactly 84 marks, so we can write the equation:
(A + B + C) / 3 = 84
To find the average for all four tests, we need to consider the fourth test score of 96. The total marks for all four tests would be:
A + B + C + 96
The average for all four tests is then (A + B + C + 96) / 4.
We can substitute the value of (A + B + C) from the previous equation into this equation:
(84 * 3 + 96) / 4 = (252 + 96) / 4 = 348 / 4 = 87
Therefore, the average for all four tests is 87.
Option C, 87, is the correct answer.
To find the average for all four tests, we need to calculate the sum of the scores for all four tests and divide it by 4 (the total number of tests).
Let's assume the student's scores for the first three tests are x, y, and z.
We know that the average for the first three tests is 84, so we can write the following equation:
(x + y + z) / 3 = 84
To find the sum of the scores for all four tests, we need to calculate x + y + z and add the fourth test score, which is 96.
Sum of scores for all four tests = (x + y + z) + 96
To find the average for all four tests, we divide the sum of scores for all four tests by 4:
Average = (Sum of scores for all four tests) / 4
Now, we can substitute the equation (x + y + z) / 3 = 84 into the equation for the sum of scores and simplify:
Average = ((x + y + z) + 96) / 4
= ((3 * 84) + 96) / 4
= (252 + 96) / 4
= 348 / 4
= 87
Therefore, the correct answer is C. 87.