Average of 2/3rd of a class is 17.What should be average of 1/3rd remaining students so that average of ent

Question

Average of 2/3rd of a class is 17.What should be average of 1/3rd remaining students so that average of entire class is 20?"give calculation process"

Answer 1

Let's say there are n students inthe class.

The average of the 2/3 is 17, which means those scores add up to
17 * 2/3 * n

We want to total to be 20 * n
The remainder should add up to 20n - 34/3 * n = 26/3 * n
This is for n/3 students, so their average should be
26n/3 / (n/3) = 26

If you are very comfortable with numbers you could recognize that 2/3 are 3 below the average, so the remaining 1/3 should be 6 above the average.

Answer 2

Let there be 30 students in the class. For average of 20 for the all class the total number will be =20*30=600;
2/3 of the class means 20 students have average =17,there total will be =17*20=340;
for remaining 1/3 students total number would be = 600-340=260;
Average of remaining 10 students =260/10=26;
Hence, the average of remaining 1/3 students be 26.

Answer 3

There are two set of students one set has an average of 17 i.e. 2/3rd of the class
the second set remaining 1/3rd of the class
average is
17-(20*2)
where 17 ist the average of one set
20 is the average of the whole class
2-no of sets to average.
So the answer is 23.

I think i am right

Answer 4

How about..
[(2/3)*17] + [(1/3)x] = 20

11 1/3 + (1/3)x = 20

(1/3)x = 8 2/3

x = 26

Answer 5

let there be s students with m marks of 2/3 & n marks of 1/3
m/(2/3*s)=3m/2s=17=>m/s=34/3
n/(1/3*s)=3n/s=x
m+n=total marks
so (m+n)/s=20=>m/s+n/s=20
=>34/3+x/3=20=>x/3=(60-34)/3=26/3
so the required ratio is 26

Answer 6

let there be x students in the class.
so,total marks of 2/3rd students=17*x*2/3

Total marks of the entire class=20*x

so, total marks of the remaining students=20x - 34x/3
=26x/3

number of remainin students=x/3

so, average marks of remainin students=(26x/3)/(x/3)
=26

Answer 7

(2/3)*17+(1/3)x=20
34+x=60 I just multiplied both sides by 3
so x=26