Regra de três composta com Macete

Compound Rule of Three with a Trick In this video, I explain how to solve compound rule of three problems using a trick. You'll need to ask questions to determine whether the quantities are directly proportional or inversely proportional. This method is especially useful because it makes calculations easier and helps students who have difficulty orienting the arrows. Compound Rule of Three 1. A brickyard produces 1,470 bricks in 7 days, working 3 hours a day. How many bricks will it produce in 10 days, working 8 hours a day? 2. Eighty bricklayers build 32 meters of wall in 16 days. How many bricklayers will it take to build 16 meters of wall in 64 days? 3. A bus travels 2,232 kilometers in 6 days, running 12 hours a day. How many kilometers will it travel in 10 days, running 14 hours a day? 4. In a factory, 12 workers working 8 hours a day can make 864 cardboard boxes. How many boxes will 15 workers working 10 hours a day make? 5. Twenty machines, working 16 hours a day, take 6 days to complete a job. How many machines will be needed to perform the same job if they work 20 hours a day for 12 days? 6. In a textile factory, 8 tailors make 360 ​​shirts in 3 days. How many tailors are needed to make 1,080 shirts in 12 days? 7. A cyclist travels 150 km in 4 days, cycling 3 hours a day. In how many days would he complete a 400 km trip, cycling 4 hours a day? 8. At a boarding school, 35 students spend 15,400 reais on meals for 22 days. How much would 100 students spend on meals for 83 days at this boarding school? 9. 27.4 kg of wool were used to weave 24 meters of cloth 60 cm wide. How long could the cloth be woven with 3.425 tons of wool to obtain a width of 90 cm? 10. Two-fifths of a project were completed in 10 days by 24 workers, who worked 7 hours per day. In how many days could this project be completed, knowing that 4 workers were furloughed and that they now work 6 hours per day? 11. The consumption of 12 identical light bulbs, lit for 5 hours per day, over 39 days is 26 kilowatts. Keeping only 9 of these bulbs lit for 4 hours per day, how much will the consumption be in 30 days? 12. If 15 kg of paper corresponds to 3,000 sheets measuring 20 cm wide by 30 cm long, how many sheets measuring 15 cm by 20 cm will correspond to 7 kg of paper? 13. 1,064 kg of hay are needed to feed 14 horses for 12 days. How much hay would be needed to feed 6 horses for 60 days? 14. 30 workers spend 15 days of 8 hours each to build a 52 m wall. How many days of 9 hours will it take 25 workers to build an equal 39 m wall? 15. 6 workers completed half of the work they were assigned in 15 days. At the end of that time, 4 workers left the job. How long will it take for the remaining workers to finish the job? 16. A fleet of trucks traveled 3,000 km to transport goods, averaging 60 km per hour, and took 6 days. How many days would it take for this same fleet to travel 4,500 km at an average speed of 50 km per hour under the same conditions? 17. The production of 400 hectares, where 50 men work, supports 5 families. How many families could be supported, under the same conditions, with 600 hectares and 60 men working? 18. If 16 men spend 10 days assembling 32 machines, the number of days it would take 20 men to assemble 60 machines is: 19. A vehicle travels a certain distance at a constant speed for 3 hours. How long would it take to travel 2/3 of that distance at a constant speed that was 3/5 of the previous speed? 20. A project was completed in 60 days using 5 bricklayers and 10 apprentices. Knowing that the work of two apprentices is equivalent to that of one bricklayer, how many days would it take to complete the same project if we had 6 bricklayers and 12 apprentices? Video link:    • Regra de três composta com Macete