APRENDE A RESOLVER MAGNITUDES DIRECTAMENTE PROPORCIONALES EN 5 MINUTOS

Definition. Two quantities are said to be directly proportional if multiplying or dividing one of them by a number results in the other being multiplied or divided by the same number. The ratio or quotient between the second and first quantities is called the constant of direct proportionality. One way to solve problems involving directly proportional quantities is by using the rule of three. However, this procedure can become a completely mechanical method, without a real understanding of what is being done. Let's solve the exercises using another procedure, which we could call unitary, in which we will calculate the value of the second quantity that corresponds to the value of 1 of the first quantity. This calculated value is what we previously called the constant of direct proportionality. Problem 1: The math teacher has many exams to grade, but prefers to dedicate a significant amount of time to each exam to avoid making mistakes. After several hours, he has realized that he grades 3 exams per hour. How many exams has he graded in 2, 3, 4, 5, and 6 hours? Problem 2: Carlos notices at supermarket D1 that 3 bottles of water cost $2,700. If he buys 12 bottles, how much will he have to pay? #directlyproportionalquantity