the mean marks of 150 students of a class is 65.6 . the mean marks of bous is 60 and mean marks of girls is 72 find number of girls and boys in the class
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Step-by-step explanation:
Total students in class =150
mean weight=60kg
total weight =150×60=9000kg
Let the total number of boys =x
mean weight of boys =70kg
total weight of boys =70×x=70xkg
total number of girls = total students - no. of boys =150−x
mean weight of girls=55kg
total weight of girls =55×(150−x)=55×150−55x=(8250−55x)kg
Total weight = weight of boys + weight of girls
9000=70x+(8250−55x)
9000=70x+8250−55x
9000−8250=70x−55x
750=15x
x=
15
750
x=50
So number of boys =50
number of girls =150−50=100
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