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The average weight of boys in the class is 50 kg and girls is 70 kg. If the average weight of whole class is 55.Find the ratio of boys and girls in the class

The average weight of boys in the class is 50 kg and girls is 70 kg. If the average weight of whole class is 55.Find the ratio of boys and girls in the class Correct Answer 3 : 1

Given

The average weight of boys in the class is 50 kg and girls is 70 kg

The average weight of whole class is 55

Concept used

Mixture and alligation concept used

Calculation

Let number of boys be x and girls be y

Total weight of boys = x × 50

Total weight of girls = y × 70

Total student = 55(x + y)

⇒ 50x + 70y = 55x + 55y

⇒ 5x =  15y

⇒ x : y = 3 : 1

∴ The ratio of boys and girls in the class is 3 : 1.

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