+9479 total number of points = ( 2 * number correct ) - ( 0.5 * number incorrect )
a. score = ( 2 * 30 ) - ( 0.5 * 5 ) = 60 - 2.5 = 57.5
b. No, you must know the number correct and the number incorrect to determine the score.
c. We want to set the score equal to 80 and solve for the number incorrect.
Also...let's say c = number correct and w = number incorrect
80 = 2c - 0.5w We want to solve this equation for w . Subtract 2c from both sides.
-2c + 80 = -0.5w Multiply both sides by -2 .
4c - 160 = w
w = 4c - 160
d. To graph it, we can say y = w and x = c .
y = 4x - 160 To find the x-intercept, plug in 0 for y and solve for x .
0 = 4x - 160
40 = x The x-intercept is 40 .
When there are 0 incorrect, there must be 40 correct to get 80 total points.
y = 4x - 160 To find the y-intercept, plug in 0 for x and solve for y .
y = 4(0) - 160
y = -160 The y-intercept is -160 .
When there are 0 correct, there must be -160 incorrect to get 80 total points.
Realistically...that is impossible to do!!!
e. Using the points we just found: (40, 0) and (0, -160)
slope = [-160 - 0] / [0 - 40] = 160/40 = 4
For every 4 additional wrong answers, there must be 1 additional right answer.
f. w = 4c - 16 If c = 43 , then
w = 4(43) - 160 = 12
The student must answer 12 questions wrong to get 80 points on the test.
But 43 + 12 = 55 , and there are only 50 questions on the test.
The student cannot get 12 wrong and 43 correct because there aren't enough questions. It's impossible for the student to get exactly 80 points on the test if he gets 43 correct.
The most he can get correct is 42 , which means he must get 8 wrong....remember....this is in order to get exactly 80 points on the test...no more, no less!
+154 Answer it all if possible, you can do it in parts, like A [send] B [send] and so on...
+445 For A, since a correct answer is worth 2, and an incorrect is worth -1/2, it is simple multiplication
30*2=60
-1/2*5= -2.5
Subtract 2.5 from 60
60-2.5=57.5
In total, that leaves 57.5 points.
For B, I would have to say it is not possible to determine the score based off correct answers, due to the fact that incorrect answers deduct points, and unanswered aren't worth anything.
+9479 total number of points = ( 2 * number correct ) - ( 0.5 * number incorrect )
a. score = ( 2 * 30 ) - ( 0.5 * 5 ) = 60 - 2.5 = 57.5
b. No, you must know the number correct and the number incorrect to determine the score.
c. We want to set the score equal to 80 and solve for the number incorrect.
Also...let's say c = number correct and w = number incorrect
80 = 2c - 0.5w We want to solve this equation for w . Subtract 2c from both sides.
-2c + 80 = -0.5w Multiply both sides by -2 .
4c - 160 = w
w = 4c - 160
d. To graph it, we can say y = w and x = c .
y = 4x - 160 To find the x-intercept, plug in 0 for y and solve for x .
0 = 4x - 160
40 = x The x-intercept is 40 .
When there are 0 incorrect, there must be 40 correct to get 80 total points.
y = 4x - 160 To find the y-intercept, plug in 0 for x and solve for y .
y = 4(0) - 160
y = -160 The y-intercept is -160 .
When there are 0 correct, there must be -160 incorrect to get 80 total points.
Realistically...that is impossible to do!!!
e. Using the points we just found: (40, 0) and (0, -160)
slope = [-160 - 0] / [0 - 40] = 160/40 = 4
For every 4 additional wrong answers, there must be 1 additional right answer.
f. w = 4c - 16 If c = 43 , then
w = 4(43) - 160 = 12
The student must answer 12 questions wrong to get 80 points on the test.
But 43 + 12 = 55 , and there are only 50 questions on the test.
The student cannot get 12 wrong and 43 correct because there aren't enough questions. It's impossible for the student to get exactly 80 points on the test if he gets 43 correct.
The most he can get correct is 42 , which means he must get 8 wrong....remember....this is in order to get exactly 80 points on the test...no more, no less!
