Paper 1 · Mathematical Reasoning and AptitudeUGC NET December 2022 (11.03.2023) Shift-II (Sociology)
हिन्दी में पढ़ें →In a class of 60 students, the average height of 20 students is x centimetres, of another 20 students is y centimetres and of the remaining 20 students is z centimetres. What is the average height of the whole class?
A(x+y+z)/60 cm
B30 cm
C(x+y+z)/20 cm
D(x+y+z)/3 cm ✓ Correct
Correct answer: (D) (x+y+z)/3 cm
Explanation
The class average is (x + y + z)/3 cm.
Each group of 20 contributes total heights 20x, 20y and 20z.
Sum of all heights = 20x + 20y + 20z = 20(x + y + z).
Total students = 60.
Average = 20(x + y + z)/60 = (x + y + z)/3.
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