Common bounds and feasible counts

Common bounds and feasible counts

Secondary 2
TGM Original — E Math Summary Notes (4052), 2026 editorial manuscript

When both conditions must hold, solve them separately and keep their overlap. Translate “at most” as \(\le\) and “at least” as \(\ge\). Counts must be whole numbers, so interpret the bound before choosing a value.

Example

From \(2x+1>5\), \(x>2\). From \(3x-2\le10\), \(x\le4\). Combining \(x>2\) and \(x\le4\), the top row below shows the first condition and the lower row shows the second. Their common range is \(2<x\le4\); the integer solutions are \(3\) and \(4\).

A hire fee is \(12\) dollars plus \(7\) dollars per item, with a budget of \(50\) dollars. For \(n\) items, \(12+7n\le50\), so \(n\le\dfrac{38}{7}\). The greatest possible count is \(5\): five cost \(47\) dollars, while six cost \(54\) dollars.

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