The OA ?? do you have ??

No

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I find it easier to work with numbers, so I made 80 the average score for the initial exam. We know that Jovan was initially 6.2 points above the average (80+6.2 = 86.2).

To calculate the total combined points for the entire class, you would multiply the average by the number of students.

80 (25) = 2000

If Jovan was the only one to earn 10 extra points, you would add 10 to the combined points to get the new total

2000+10 = 2010

Then, to find the new average, you would multiply this by 25

2010/25 = 80.4

If you add the extra points to Jovan's initial score, it now is:

86.2+10 = 96.2

Then you take that number and subtract the average score, this will give how many points Jovan is above the average.

96.2-80.4= 15.8 points.

Algebraically:
Let initial marks be x.
x - (y+x)/25 = 6.2 ; y being marks of the rest.
So,
after getting 10 marks.
x+10 -(y+x+10)/25
= x - (y+x)/25 + 10 - 10/25
= 6.2 + 9.6
= 15.8
I hope this helps.

If sum of score = Y
And initial mean = X

Then Y/25 = X

So Y = 25X

New mean will be
25X + 10/25 = X + 0.4

Jovan initial score = X + 6.2 + 10

So value above mean = X + 6.2 + 10 - X-0.4 = 15.8

Let initial average of group be x


So initial sum of scores

x = sum/25

Sum = 25x

Let new average be y


Y = 25x + 10/25

Jovan initial score = x + 6.2

Jovan new score x + 16.2


Therefore x + 16.2 - ( 25x + 10/25)

= 15.8.

Adewale Fasipe GMAT, GRE quant instructor from Nigeria.

https://www.teacheron.com/tutor-profile/8tG7?r=8tG7