Choose an arbitrary fraction.

Let one of the fractions be 4/5 say, we want a fraction x such that:

(4/5)/x = 3 1/4 = 13/4

=> x = (4/5)/(13/4) = (4/5)*(4/13)=16/65

so, one pair of such fractions is 4/5 and 16/65

For the second pair, choose another arbitrary fraction.

Let one of the fractions be 7/4 say, we want a fraction x such that:

(7/4)/x = 13/4

=> x = (7/4)/(13/4) = (7/4)*(4/13) = 7/13

so another pair of fractions with the desired property is 7/4 and 7/13