Question

There are 100 students in a class The mean height of the class is 150 cm If the mean hegh
60 boys is 170 cm, find the mean height of the girls in the class.
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Answer 1

Dear friend,

Total no. of students = 100

Total no. of boys = 60

So, Total no. of girls = 100 - 60 = 40

Mean height of 100 students = 150 cm

Then, Total height of 100 students = 150 × 100 = 15000 cm

Mean height of 60 boys = 170 cm

Then, Total height of 60 boys = 170 × 60 = 10200 cm

Then,

Total height of 40 girls = Total height of class - Total height of boys

= 15000 - 10200 = 4800 cm

Mean height of 40 girls = Total height of 40 girls ÷ No. of girls

= 4800 cm ÷ 40

= 120 cm

Answer: Mean height of the girls = 120 cm.

Hope it helps !!!