let's name all the purchases "x"
so [tex] \frac{4}{25} [/tex]of them were stuffed animals, and out of that [tex] \frac{10}{21} [/tex] were bears.
to get the results we have to multiply the fraction of bears by the fraction of the stuff animals:
[tex] \frac{4}{25}*\frac{10}{21} [/tex].
and now we simplify:
[tex] \frac{4*2}{5*21} [/tex]=[tex] \frac{8}{105} [/tex]
and this is the answer!