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 fraciton 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. 