Algebra, STD2 EQ-Bank 1 MC \(Q\) varies directly with \(r\) and \(Q=2\) when \(r=16\). The value of \(r\) when \(Q=13\) is \(1.625\) \(26\) \(76\) \(104\) Show Answers Only \(D\) Show Worked Solution \(Q \propto r \ \Rightarrow \ Q=kr\) \(\text{Find \(k\) given \(\ Q=2\) given \(\ r=16\):}\) \(2=16 \times k \ \Rightarrow \ k=\dfrac{1}{8}\) \(\text{Find \(r\) when \(\ Q=13:\)}\) \(13\) \(=\dfrac{1}{8} \times r\) \(r\) \(=13 \times 8=104\) \(\Rightarrow D\)