A $6.5\times$ pair of binoculars has an objective focal length of 26 cm. If the binoculars are focused on an object 4.0 m away (from the objective), what is the magnification? (The $6.5\times$ refers to objects at infinity; Eq. 25–3 holds only for objects at infinity and not for nearby ones.)
Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.