If $a \div b = 2$ and $b \div c = \frac{3}{4}$, what is the value of $c \div a$? Express your answer as a common fraction.
a/b = 2
b/c = 3/4 → c / b = 4/3
(c / b) (4/3) 4 2 c
______ = _____ = ___ = ___ = ___
(a / b) 2 6 3 a
+230 
