SOLUTION: A teacher told Melinda that she has a course average of 78 based on her six math tests. When she got home, she found 5 of her tests with scores of 87, 63, 79, 71, and 96. She cou

Question 442917: A teacher told Melinda that she has a course average of 78 based on her six math tests. When she got home, she found 5 of her tests with scores of 87, 63, 79, 71, and 96. She couldn't find the sixth test. What score did she obtain on that test?
Found 2 solutions by ankor@dixie-net.com, Leaf W.:
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A teacher told Melinda that she has a course average of 78 based on her six math tests.
When she got home, she found 5 of her tests with scores of 87, 63, 79, 71, and 96.
She couldn't find the sixth test. What score did she obtain on that test?
;
Let x = score on the lost test
:
= 78
:
= 78
Multiply both sides by 6
x + 396 = 6(78)
x + 396 = 468
x = 468 - 396
x = 72 is the score of the lost test

Answer by Leaf W.(135) (Show Source): You can put this solution on YOUR website!
The average of a set of values is the sum of the values divided by the number of values. In this case (using x as the unknown value/test score), the values are 87, 63, 79, 71, 96, and x. The number of values/test scores is six, and you know that the average is 78. Therefore, you can use the equation . Next, solve for x:
Multiply both sides of the equation by 6:
Simplify the right side of the equation by adding the values/test scores together:
Subtract 396 from both sides to isolate x:
Therefore, the missing test score must be 72.
RELATED QUESTIONS
Amy has an 85 average on her five math tests. Her teacher tells her she can drop her... (answered by KMST)
Linda has an 80 average on her 11 math tests. Her teacher tells her she can drop her... (answered by josgarithmetic)
A student has scores of 83, 89, 78, and 86 on her first four tests. what score must she... (answered by scott8148)
Naomi had an average score of 70 on her science tests. On her next test, she got a 90 and (answered by ankor@dixie-net.com,polas4sure@gmail.com)
In a certain course, Amy received an average (arithmetic mean) score of 84 for her first... (answered by alicealc)
A student has a mean (average) score of 88 in her math class. This is the average of her... (answered by josmiceli,greenestamps)
Kellie's parents give her $2 for each test grade above 90 that she brings home. Which is... (answered by JulietG)
Moira is getting ready for college. She needs to have a grade of at least 85 in her Math... (answered by Alan3354)
Emily's gold is six weeks is to earn a grade of at least 95 in her English one honors... (answered by fractalier)