is inactive between the
                        30th and 40th minutes (we have <img class="math"
                                                            src="../_images/math/904835a0316c9eb7be781e9a85f5785d0003bcf3.png"
                                                            alt="W = ([0,60] \times \{A,B\}) \cup ([0,30] \times \{C\}) \cup ([30,60] \times \{C\})"/>).
                    </p>
                    <p>Individual <img class="math" src="../_images/math/211284f68205c3e66773eaf026f32a0acdd3d