Direct Variation Example - Maths Online Tutoring

Direct Variation Example - Maths Online Tutoring Direct variation example involves problems with one variable that is directly proportional to other variable. The relationship between two variables in direct variation is that one variable is a constant multiplication of another. In simple words, if one variable is product of other variable and a constant, then two variables are said to be in direct variation. For example, if y is directly proportional to x and k is a non zero constant then y = k * x Problem 1: y is directly proportional to x, and when x=6 then y=30. What is the constant of proportionality? Solution: Given: y is directly proportional to x. So y = k x = Put the values we know (y=30 and x=6): = 30 = k * 6 by dividing both sides by 6 = 30/6 = k * 6/6 = 5 = k 1 = k = 5 = The constant of proportionality is 5: So the equation is y = 5 x Problem 2: If y varies directly as x, and y = 24 when x = 16, find y when x = 7 Solution: Given: y varies directly as x, so y = k x = Using the given values find value of constant k = We know y = 24 and x= 4, = So the equation is 24 = k * 4 = Divide by 4 on both sides, = Thus, value of k = 6. = When x = 7 then y = k x = 6 * 7 = 42 = Thus the value of y = 42 when x =7.