Question

The mean weight of 150 students in a certain class us 60kg. The mean weight of the boys from the class is 70kg, while that of gis is 55kg. What is the number of girls in the class

Answer 1

The mean weight of 150 students is 60 kg  

Therefore, Total weight of 150 students = (150×60)Kg=9000Kg  

Now, mean weight of all boys from the class is 70 kg and mean weight of all girls from the class is 55 kg.  

Let the number of girls be x, then number of boys be (150 - x)  

Therefore, Total weight of class = weight of all boys + weight of all girls  

9000=(150−x)×70+55x

9000=10500−70x+55x

15x=10500−9000

15x=1500

x = 100

Total number of girls in the class are 100.

Answer 2

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