Answer: She will have to spend 8 days on vacation before she will have bought a total of 16 souvenirs.
Step-by-step explanation:
Given: Ann bought 4 souvenirs during 2 days of vacation.
Per day she buys =[tex]\dfrac{4}{2}=2[/tex] souvenirs [unit rate]
To buy 16 souvenirs , she will take [tex]\dfrac{16}{2}[/tex] = 8 days.
Hence, she will have to spend 8 days on vacation before she will have bought a total of 16 souvenirs.