The number of ways by which exactly 2 people are taller than the person behind them is; 6.
<h3>What number of ways can they line so that exactly two people are taller than the person behind them?</h3>
It follows from content that since 4 individuals with different heights are to line up, the 2 individuals who must be taller than the person behind them are represented as one entity and must be in the 1st and 2nd position or the 2nd and 3rd position.
Hence, the number of ways is; 6 upon counting the number of possible outcomes.
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