Solution: To determine the average (arithmetic mean) height per pupil, we need the heights of all people or mean height of girls & boys and their ratio.

Statement 1: The average (arithmetic mean) height of the girls in the class is 61 inches

As we don't know the average height of boys, this statement alone is insufficient

Statement 2: The average (arithmetic mean) height of the boys in the class is 64 inches

As we don't know the average height of girls, this statement alone is insufficient

Combining 1 & 2, still we don't know the exact number of boys and girls or their ratio, we can't determine the average of the group.

Answer E

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