Answer:
12 days
Explanation:
Given:
s = d
Where,
d = number of days he spends on vacation
s = total number of souvenirs he buys
How many days will Mark have to spend on vacation before he will have bought a total of 12 souvenirs?
s = 12
Since,
s = d
Then,
12 = d
Therefore, Mark will have to spend a total of 12 days on vacation before he will have bought a total of 12 souvenirs