Pulleys
One of the lifts just broke down in a critical area at the Big Dig. It will take a week to repair the lift, and construction must go on. Bags of concrete that weigh 75 pounds each must be lifted from the ground to a platform 100 feet in the air. One of the engineers on the project suggests that they use pulleys to lift the bags onto the platform. Unfortunately, the only suitable weight for the task is 50 pounds.
Sketch out a pulley system that will allow them to lift the 75 pound bags of concrete with 50 pound weights.