What is the correct way to find the average percentage of 4 test scores. 28 out of 100, 40 out of 50, 40 out of 50 and 60 out of 100. Do you add the two out of 50 (40+40=80 out of 100) and divide 28/100, 80/100, 60/100 by 3. OR do I convert the two 40/50 to 80/100 and then add 28/100, 80/100, 80/100 and 60/100 and divide by 4. They both sound logical but you come up with two different answers.
Math - What is the correct way to find the average percentage of 4 test scores?
- Posted:
- 3+ months ago by patrickha...
- Topics:
- score, math, maths, percentage
Details:
Responses (1)
"The average percentage of 4 test scores: 28 out of 100, 40 out of 50, 40 out of 50 and 60 out of 100."
Let's write that properly:
(28/100 + 40/50 + 40/50 + 60/100) / 4
Find the common denominator:
(28/100 + (2/2)(40/50 + 40/50) + 60/100) / 4 =
(28/100 + 80/100 + 80/100 + 60/100) / 4 =
and do the sums
((28 + 80 + 80 + 60) / 100) / 4 = (248 / 4) / 100 = 62 / 100 = 62% or
(0.28 + 0.8 + 0.8 + 0.6) / 4 =
2.48 / 4 = 0.62 , which corresponds to 62%.
Thanks for your reply. That is the way I would have done it. These are 4 marks on my sons report card. The reason I asked this is because his teacher gave him an average of 56%. It's obvious the teacher did ((28 + 80 + 60) / 100) / 3 = (168 / 3) / 100 = 56%. That's a 6% difference on his average. Time for a meeting with the teacher. Makes me wonder how many students have been ripped off and for how long. Thanks again.