Please solve asap with answers and work don't do explaining 3&4

3. The focal length of the eyepiece of a certain microscope is 30.0 mm. The focal length of the objective is 20.0 mm. The distance between objective and eyepiece is 25.0 cm. The final image formed by the eyepiece is at infinity. Treat all lenses as thin. What is the distance from the objective to the objective being viewed? What is the magnitude of the linear magnification produced by the objective? What is the overall angular magnification of the microscope? 4. In young's experiment with the two slits separation of 6.0 x 10 m and interference pattern on a screen 4.0 m away. If the seventh bright fringe above the central fringe is a linear distance of 20 cm above the central fringe, what is the wavelength of light used in the experiment? What is the color of the light? What is the linear distance from the central bright fringe to the seventh dark fringe above it