Neco Model Questions Vol1 2017 Biology Question 34

A person's blood calcium concentration is initially \(2.0\ \text{mM}\) (normal range 2.2-2.6 mM). Low calcium triggers parathyroid hormone (PTH) which, per hour, increases calcium reabsorption in the kidneys by \(0.15\ \text{mM}\) and stimulates bone resorption releasing \(0.25\ \text{mM}\). The kidneys also lose calcium at a baseline rate of \(0.05\ \text{mM\,h}^{-1}\). When calcium is below \(2.2\ \text{mM}\), calcitonin secretion is suppressed, reducing this baseline loss by \(0.1\times(2.2-Ca)\) mM h\(^{-1}\). No dietary calcium is taken in. Assuming the processes act continuously and that calcium cannot exceed the normal upper limit of \(2.6\ \text{mM}\), what is the blood calcium concentration after 3 hours (to one decimal place)?