Total students in two English classes= 48

(1) The avg. height of class with the larger number of students is 70 inches - No information about the number of students in that class and about the avg. height of other class. Insuff.

(2) The avg. height of class with the smaller number of students is 4/5 of the average height of other class - No information about the avg. height of other class.

(1) & (2) together,

the avg. height of one class is 70 and the avg. height of other class is 4/5*(70) = 56. No information about the number of students in any class. Insuff.

Ans: E.

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