The average marks of boys in class is 52 and that of girls is 42. The average marks of boys and girls combined is 50. The percentage of boys in the class is
80
60
40
20
As we learnt in
ARITHMETIC Mean -
For the values x1, x2, ....xn of the variant x the arithmetic mean is given by
in case of discrete data.
let us donote sum of marks scored by boys as and that by girls as
,the no. of boys and girls be
and
respectively,
Then average
average
average
From (1), (2) and (3), we have
&
playing in 3
Let us denote then
Hence,
Hence,
80%
Option 1)
80
Correct option
Option 2)
60
Inorrect option
Option 3)
40
Inorrect option
Option 4)
20
Inorrect option
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