Question

72. In an examination average marks obtained
by the girls of a class is 85 and the average
marks obtained by the boys of the same class is
87. If the girls and boys are in the ratio 4: 5,
average marks of the whole class
approximately) is closest to
s, the
month
a) 85.9
b) 86.1
7 for
c) 86.4
d) 86.5​

Answer 1

Answer:

let in class there are total 9x student

so the number of girls = 4x

and number of boys = 5x

total marks scored by girls = 4x*85= 340x

totalarks scored by boys =5x*87= 435x

total marks scored by class =

435x + 340x =775x

average marks of whole class = 775x/9x =86.1