Dividing Rational expressions

i don't think that the answer in the book is right for this one

$\displaystyle \frac{15a^2b}{4c} \div \frac{8abc}{-3}$

i know that you have to times it by the reciprocal

the non-reduced answer that i got is:

$\displaystyle -\frac{45a^2b}{60a^2bc}$

the only way that i can think to reduce this is by dividing the top and bottom by 5 but that leaves 9 on the top and 12 on the bottom which can be reduced further.

also

the answer in the back of the book is

$\displaystyle -\frac{45a}{32c^2}$

is this the correct answer??

how do you get it if it is.