Question 986378: So far this semester your test scores have been 75, 91, and 85. Set up and solve an equation for each problem.
a. If all of the tests are equally weighted, what score must you get on the fourth test to have a test average of 88? Define any variable used.
b. If the fourth test counts twice as much as the other three tests, then what score must you get on the fourth test to have a test average of 90? Define any variable used.
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! So far this semester your test scores have been 75, 91, and 85.
Set up and solve an equation for each problem.
:
a. If all of the tests are equally weighted, what score must you get on the fourth test to have a test average of 88? Define any variable used.
let a = the 4th test grade
 = 88
multiply both sides by 4, add the grades
251 + a = 4(88)
a = 352 - 251
a = 101 to have an 88 average, (you may need extra credit here)
:
b. If the fourth test counts twice as much as the other three tests, then what score must you get on the fourth test to have a test average of 90? Define any variable used.
let b = test grade for this to be true,
Treat it like there are two grades of b, and average 5 tests
 = 90
Multiply both sides by 5
251 + 2b = 5(90)
2b = 450 - 251
2b = 199
b = 199/2
b = 99.5 required to get a 90 average
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