A farsighted man uses eyeglasses with a refractive power of 1.75 diopters. Wearing the glasses 0.02 m from his eyes, he is able to read books held no...

A farsighted man uses eyeglasses with a refractive power of 1.75 diopters. Wearing the glasses 0.02 m from his eyes, he is able to read books held no closer than 0.28 m from his eyes. He would like a prescription for contact lenses to serve the same purpose. What is the correct contact lens prescription, in diopters?