Final answer:
To attain a healthy BMI, Dennis would need to lose approximately 137.6 pounds.
Step-by-step explanation:
To attain a BMI that is considered a healthy weight, we need to determine the maximum weight that would result in a BMI of 24.9, the upper limit of the normal weight range. In order to do this, we can use the BMI formula: BMI = weight (in kg) / height^2 (in meters). Since Dennis's BMI is currently 30, we can set up the equation as 30 = 217 / height^2. Solving for height, we find that height^2 = 217/30. Taking the square root of both sides, we get height = sqrt(217/30), which is approximately 180cm. Now, to calculate the weight associated with a healthy BMI of 24.9, we can use the formula: weight = BMI x height^2. Plugging in the values, we have weight = 24.9 x (180/100)^2, which gives us a weight of approximately 79.4 kg. Therefore, Dennis would need to lose approximately 137.6 pounds (62.6 kg) to reach a BMI that is considered a healthy weight.