Two traffic lights turn red together at exactly 5: 00 pm. one light is on a 36-second cycle from red back to red while the other is on a 48-second cycle. at what time will they again turn red together? give the exact time, including seconds

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?