Question

A 16 year old girl is 1.75 m tall & weighs 125 lbs. She thinks she is fat and overweight.NB: 1Kg = 2.2 lbs (a) How can she prove if she is? (1mk) (b) Is she? (3mk)

Answer 1

To determine whether the girl is overweight or not she needs to calculate the body mass index (BMI). The equation of the BMI is the following:

`\text{BMI}=\text{ }\frac{\text{weight}}{hight^2}`

In this case the hight of the girl is 1.75 m and the weight is 125lbs, but in order to calculate de BMI the wight must be in Kg.

To calculate the weight in Kg we use the following equation:

`\text{Wight in Kg = }\frac{125\text{ lbs}}{2.2\text{ lbs/Kg}}\text{ = 56.82 Kg}`

Now, the BMI can be calculated as:

`\text{BMI}=\text{ }\frac{56.82\text{ Kg}}{(1.75m)^2}=18.55Kg/m^2`

In order to determine if the girl is overweight or not we need to look for the BMI categories and compare the value 18.55 Kg/m2 to them.