The half-lives in two different samples, A and B, of radioactive nuclei are related according to T,B

Question:

The half-lives in two different samples, A and B, of radioactive nuclei are related according to T½,B = ½T1/2,A · In a certain period, the number of radioactive nuclei in samples A decreases to one-fourth the number present initially. In this same period, the number of radioactive nuclei in sample B decreases to a fraction f of the number present initially. Find f.