A student made 60 and 68 his first two exams. Needs to pass the class with a 67 average. What does his third exam need to be in order to pass?
What is the problem and solution? Thank you!
2007-09-17 01:05:58 · 14 answers · asked by Vonnie 2 in Science & Mathematics ➔ Mathematics
you need the average of the 3 exams to be 67
so
(60+68+x)/3 = 67
solve for x
answer: x = 73
the end
.
2007-09-17 01:12:47 · answer #1 · answered by The Wolf 6 · 2⤊ 0⤋
Let x be the score of the 3rd last exam. Then
total score = 60 + 68 +x
average = ( 60 + 68 + x ) /3 = 67
128 + x = 67(3) = 201
x = 201 - 128
or x = 73
The student needs to score 73 on the last exam.
2007-09-17 01:15:07 · answer #2 · answered by vlee1225 6 · 2⤊ 0⤋
We know an average is calculated by the sum of the scores (60 + 68 + {unknown} ) and divided by the number of scores, so:
1/3(60+68+x)=67 (Form an equation form the data)
201 = 60+68+x (Get rid of the 1/3)
201 - 60 - 68 = x (Collect like terms)
x = 73 (Solution!)
So the student needs to get 73 on the final exam.
2007-09-17 01:23:51 · answer #3 · answered by tinned_tuna 3 · 0⤊ 0⤋
Since the average for the 3 exams is 67, the total for the 3 exams is 67*3 = 201.
Final exam marks = 201-60-68 = 73.
2007-09-17 01:20:19 · answer #4 · answered by glade_moonstone 3 · 0⤊ 0⤋
The 1st exam was 60 or 7 less from 67 pass score
The 2nd exam was 68 or 1 over from 67 pass score
He needs for the 3rd exam at least 67+7-1 = 73
2007-09-17 01:55:02 · answer #5 · answered by Anonymous · 0⤊ 1⤋
hello...i'm gonna give you a step-by-step solution:
okay. in getting the general or total score of this type of problem, we must get first the total sum of the items then divide it,just lilke in your example, there must be three grades to get the general average 67. so the solution is here:
x is the third grade to have 67...
so:
60 + 68 + x / 3 = 67
we put x on the third grade because we do not know yet the third grade, isn't it?
then the next:
128 + x / 3 = 67
multiply both sides by 3 to eliminate the denominator 3 on the left side....
3 ( 128 + x / 3 = 67) 3
thus cancel all 3s....
and we are going to have 128 + x = 201
and then transpose 128 to the right side because we have to follow the rule that is to combine similar terms....but as we transpose it to the other side, we must put the negative sign which is its opposite...
x = 201 - 108
x = 73
2007-09-17 01:35:32 · answer #6 · answered by Ninik 3 · 0⤊ 1⤋
(60+68+x)/3 = 67
128 + x = 67 x 3
128 + x = 201
x = 201 - 128
x = 73
the student needs 73 to pass the exam.
2007-09-17 01:36:21 · answer #7 · answered by Anonymous · 0⤊ 0⤋
60+68+x=67*3
60+68+x=201
128+x=201
128-128+x=201-128
x=73
73 needed to pass
2007-09-17 03:42:00 · answer #8 · answered by Dave aka Spider Monkey 7 · 0⤊ 1⤋
let him get x in the third test.
given (60+68+x)*1/3=67
or 128+x=201
or x=73
2007-09-17 20:15:28 · answer #9 · answered by Sumita T 3 · 0⤊ 0⤋
73..you can calculate it by
67 x 3 = 201
201 - 60 - 68 = 73
gud luck
2007-09-17 01:20:53 · answer #10 · answered by leeza 1 · 0⤊ 0⤋