List of top Data Sufficiency and Logical Reasoning Questions on Data Sufficiency - Averages asked in SNAP

What is the average height of the class?
(I) Average height of the class decreases by 1 cm if we exclude the tallest person of the class whose height is 56 cm.
(II) Average height of the class increases by 1 cm if we exclude the shortest person of the class whose height is 42 cm.