Question

In a class, there are 54 students. 33 % of the number of students are boys and rest are girls. The average score in mathematics of

boys is 50% more than that of the girls. If the average score of all the students is 70, then what is the average score of the boys?​

Answer 1

Answer:

Average score of boys in mathematics = 84.

Step-by-step explanation:

No. of boys : -

33 % of 54

33 / 100 * 54

18

∴ No. of boys = 18

∴ No. of girls = 54 - 18 = 36

Let the average score of boys in mathematics be x and that of girls be y.

∴ x = 50 % of y + y

x = 50y / 100 + y

x = y / 2 + y

x = ( y + 2y ) / 2

x = 3y / 2     ------------- 1

∵ x + y / 2 = 70

∴ y = 140 - x   ------------ 2

Subs. 2 in 1 : -

x = 3y / 2

x = 3 ( 140- x ) /2

x = 420 - 3x / 2

2x + 3x = 420

x = 420 / 5

x = 84

∴ Average score of boys in mathematics = 84.