let's call animals "a", and birds "b", birds of prey, "p"
so, b=[tex] \frac{3}{28} a[/tex]
and p=[tex] \frac{4}{15} b[/tex]
what;s the relation of p to a?
we substitude b into the last one:
and p=[tex] \frac{4}{15}* \frac{3}{28} a [/tex]
so:
p=[tex] \frac{4*3}{15*28} a [/tex]
p=[tex] \frac{4*1}{5*28} a [/tex]
p=[tex] \frac{1*1}{5*7} a [/tex]
p=[tex] \frac{1*1}{35} a [/tex]
which is the answer!
