18. There are 100 students in a class.The mean height of the class is

1.	18. There are 100 students in a class.The mean height of the class is 150cm. If the mean height of 60 boys is70 cm, find the mean height of thegirls in the class.
Answer» Number of students = 100number of boys = 60Then number of girls = 100 - 60= 40 Given, Mean Height of class = 150 cmMean Height of boys = 70 cm Sum of height of all students= 150100= 15000 cm Sum of height of all boys= 7060= 4200 cm Sum of height of girls= 15000 - 4200 = 10800 Mean Height of girls= 10800/40 = 270 cm mean = all of observation total no. of observation = 18+100+150+60+70 2 =. 199

18. There are 100 students in a class.The mean height of the class is 150cm. If the mean height of 60 boys is70 cm, find the mean height of thegirls in the class.

Answer»

Number of students = 100number of boys = 60Then number of girls = 100 - 60= 40

Given, Mean Height of class = 150 cmMean Height of boys = 70 cm

Sum of height of all students= 150*100= 15000 cm

Sum of height of all boys= 70*60= 4200 cm

Sum of height of girls= 15000 - 4200 = 10800

Mean Height of girls= 10800/40 = 270 cm

mean = all of observation total no. of observation = 18+100+150+60+70 2 =. 199