Question: A farsighted man uses eyeglasses with a refractive power of 3.80 diopters. Wearing the glasses 0.0250 m from his eyes, he is able to read books held no closer than 0.280 m from his eyes. He would like a prescription for contact lenses to serve the same purpose.
Part A: What is the correct contact lens prescription, in diopters?
I don't know how to get that answer for the above question. Please help! Thanks.