Question

6.
The average mark scored by girls is 68 and that of the boys is 62. The average marks of the
whole class is 64. The ratio of the girls and boys in the class is :
लड़कीयों और लड़कों के औसत प्राप्तांक क्रमशः 68 और 62 है और पूरी कक्षा के औसत प्राप्तांक 64 है,
तो लड़कियों और लड़कों की संख्या का अनुपात है -
(A)1:1
(B) 1 : 2
(C)2:3
(D)3:5
​

Answer 1

Answer:

Total score of boys and girls= (no. Of boys +no. Of girls)*64

Let the no. Of boys be x and girls be y.

62x+68y=(x+y)*64

62x-64x=64y-68y

2x=4y

X:y=1:2

Hope it helps u...

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Answer 2

Answer:

The correct answer is option (B) 1:2

Step-by-step explanation:

Given,

The average mark scored by girls = 68

The average mark scored by boys = 62

The average mark scored by the whole class = 64

To find:

The ratio of the girls and boys in the class

Recall the formula

Average = $\frac{Sum\ of\ all\ values}{Total\ number\ of\ values}$

Solution:

Let 'x' be the number of girls and 'y' be the number of boys in the class

Since the average mark scored by girls = 68, we have

68 = $\frac{Total \ marks \ of \ girls}{x}$

Total marks of girls = 68x

Since The average mark scored by boys = 62, we have

62 = $\frac{Total \ marks \ of \ boys}{y}$

Total marks of boys = 62y

Total marks of all the students =68x+62y

Total number of students in the class = x+y

Since the average mark scored by the whole class = 64

64 = $\frac{total\ marks\ of\ all\ the\ students }{total\ number\ of\ students}$

64 =  $\frac{68x+62y}{x+y}$

64(x+y) = 68x +62y

64x +64y = 68x +62y

64y - 62y = 68x - 64x

2y = 4x

4x = 2y

$\frac{x}{y} = \frac{2}{4} = \frac{1}{2}$

x:y = 1:2

The number of girls : The number of boys = 1:2

The ratio of the girls and boys = 1:2

The correct answer is option (B) 1:2

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