If the ratio of two numbers is 5: 2, what is the ratio of their sum to their difference?

7/3

Step-by-step explanation:

Let the two numbers be x and y which are relatively prime to each other.

a/b = 5/2

So you want the ratio of

(a + b) / (a - b)

7/3

Nice problem: Thanks for posting.

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads