Their fractions are just reciprocal of the other one. Thus, the product of the two fractions should be $1.$ 
Erik and Ivy each writes down a fraction. They are surprised to find that the fractions they write are very similar: the denominator of each fraction is exactly the same as the other\textquotesingle s numerator. What is the product of the two fractions? 
(1) $$0$$ 
(2) $\frac12$ 
(3) $$1$$ 
(4) $$2$$ 
(5) It cannot be determined. 