Question

The blood mass of a mammal is proportional to its body mass. A rhinoceros with body mass 3000 kilograms has blood mass of 150 kilograms. Find a formula for the blood mass, M, of a mammal as a function of the body mass, B, and estimate the blood mass of a human with body mass 80 kilograms.

Answer 1

The equation which equates the two is M =
`(B)/(20) = 0.05B`

A human with a body mass of 80 kilograms will have a blood mass of 4 kilograms.

Explanation:

It is said that the blood mass is proportional to the body mass.

We can say that the blood mass of a mammal is M, and that the body mass of a mammal is B.

Since the two are proportional we can write

M ∝ B , or M = kB where k is the constant of proportionality.

Using the given values for a rhinoceros we can write

150 = k × 3000

Therefore k =
`(150)/(3000) = (1)/(20) = 0.05`

Therefore the equation which equates the two is M =
`(B)/(20) = 0.05B`

A human with a body mass of 80 kilograms will have a blood mass of

=
`(80)/(20) = 4 kilograms`