Average Practice Test 1

Question : 12 of 40

Marks: +1, -0

The average height of 30 students out of 90 students is x cm and that of the remaining students is y cm. Find the average height of the whole class.

Solution:

Total height of 30 students = (30 × x) cm = 30x cm
Total height of the remaining students = (60 × y) cm = 60y cm
∴ Average height of the whole class

={30x+60y}/90

{30(x+2y)}/90

={x+2y}/3

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