Answer:
a. 47
b. 87
c. 127
Step-by-step explanation:
Assume a total of 4 exams ( first 3 plus a final)
Let final score be X,
Hence, average score = (85 + 71 + 77 + x) / 4 = (233 + x) / 4
a) to get a C, the average score must be 70
70 = (233 + x) / 4
(233 + x) = 70 (4) = 280
x = 280 - 233 = 47 (Ans)
b) to get a B, the average score must be 80
80 = (233 + x) / 4
(233 + x) = 80 (4) = 320
x = 320 - 233 = 87 (Ans)
c) to get a A, the average score must be 90
90 = (233 + x) / 4
(233 + x) = 90 (4) = 360
x = 360 - 233 = 127 (Ans)
Step-by-step explanation:
Simplify (2+5-10) and then it's -3 and then (7x)(-3) = -21
Y = -2x +8
y = x-1
y=y
-2x+8 = x-1
-3x = -1 -8
-3x = -9
3x = 9
x = 3
