Question

The specific brain mass is the brain mass divided by the body mass.Mammal A has twice the body mass of mammal B. What is the ratio of mammal A's specific brain mass to mammal B's? Report your answer using two significant figures.

Answer 1

Consider the body mass of mammal B is M. Then the body mass of mammal A will be 2M. Write down the expression for the specific brain mass of mammal A, Here m, is the brain mass of mammal A. Write down the expression for the specific brain mass of mammal B, .....(2) To find the ratio of specific brain masses of A and B. Divide equation (1) by (2). ...(3) Mimo Mg 2mg Now, the relation between the brain mass and the body mass of a mammal is Morein =( Mboth Thus, m, =(2M)07 and mg =(M)0.7

Plug these values in equation (3). M., _ (2M)0? M. 2(M) M:4 _ 20.7 M:1 = 0.812 Hence, the ratio of A's specific brain mass to B's specific brain mass is 0.812