Do you want to learn how to solve the Ratio and Proportion questions that appear in the ENEM? In this Math video lesson, you will learn how to solve ratio and proportion questions. In addition, I will solve some questions that involve the compound rule of three. To download the material in PDF format to practice, click on the link below. SUBSCRIBE TO THE CHANNEL AND LEAVE A LIKE to strengthen the List link: https://thyagoaraujo.com/listas-de-qu... Study with me and succeed in Math. ONLINE MATHEMATICS PLATFORM: https://www.thyagoaraujo.com Follow us on social media: ► Instagram: / escoladenumeros ► Twitter: / escoladenumeros Solved questions from previous ENEM exams 01. (ENEM-2013) To build a subfloor, it is common to use cement, sand and gravel in the following proportions in the composition of concrete: 1 part cement, 4 parts sand and 2 parts gravel. To build the subfloor of a garage, a construction company ordered a concrete mixer truck with 14 m³ of concrete. What is the volume of cement, in m³, in the load of concrete brought by the concrete mixer? a) 1.75 b) 2.00 c) 2.33 d) 4.00 e) 8.00 02. (ENEM-2017) In a package of flour there is a recipe for a cake, part of which is reproduced below: Having only the spoon, the measurement indicated in the recipe, a housewife had to make some conversions in order to accurately measure the flour. Consider that flour and yeast have equal densities. Each cup indicated in the recipe is equivalent to how many measuring spoons? a) 10. b) 20. c) 40. d) 80. e) 320. 03. (ENEM-2017) An industry has a fully automated sector. There are four identical machines that work simultaneously and uninterruptedly during a 6-hour workday. After this period, the machines are turned off for 30 minutes for maintenance. If any machine needs further maintenance, it will remain idle until the next maintenance. One day, the four machines needed to produce a total of 9,000 items. The work began at 8:00 a.m. During a 6-hour workday, they produced 6,000 items, but during maintenance it was observed that one machine needed to be idle. When the service was finished, the three machines that continued operating underwent new maintenance, called exhaustion maintenance. At what time did exhaustion maintenance begin? a) 4:45 p.m. b) 6:30 p.m. c) 7:50 p.m. d) 9:15 p.m. e) 10:30 p.m. 04. (ENEM-2017) At 5:15 p.m. a heavy rain begins, falling with constant intensity. A rectangular parallelepiped-shaped swimming pool, which was initially empty, begins to accumulate rainwater and, at 6:00 p.m., the water level inside it reaches 20 cm in height. At that moment, the valve is opened, releasing the water to drain through a drain located at the bottom of the pool, whose flow rate is constant. At 6:40 p.m. the rain stops and, at that exact moment, the water level in the pool has dropped to 15 cm. The moment at which the water in this pool finishes draining completely is between a) 7:30 p.m. and 8:10 p.m. b) 7:20 p.m. and 7:30 p.m. c) 7:10 p.m. and 7:20 p.m. d) 7:00 p.m. and 7:10 p.m. e) 6:40 p.m. and 7:00 p.m. 05. (ENEM-2016) A club has a soccer field with a total area of ​​8,000 m2, corresponding to the lawn. Usually, the grass on this field is mowed by two machines owned by the club for this purpose. Working at the same pace, the two machines together mow 200 m2 per hour. Due to the urgency of a soccer match, the field manager will need to request machines identical to his from the neighboring club to complete the mowing service in a maximum time of 5 hours. Using the two machines that the club already has, what is the minimum number of machines that the field manager should request from the neighboring club? a) 4 b) 6 c) 8 d) 14 e) 16