Question

the average marks scored by girls and boys are 65.1 and 71.2 respectively, Average marks scored by whole class are 70.find ratio of no of boys and girls in class

Answer 1

12ratio 49 is the right answer

Answer 2

let number of boys = x
so( total marks obtained by x boys / x )= 65.1
total marks obtained by x boys = 65.1 x
total number of girls = y
(total marks obtained by girls /y) = 71.2
total number of girls = 71.2 y
according to question
(total marks by boys and girls / x+y )= 70
(65.1 x + 71.2 y / x+y) = 70
65.1 x + 71.2 y = 70 x + 70 y
1.2 y= 4.9 x
so x : y = 12 : 49