One pipe fills a storage pool in 3 hours. a second pipe fills the same pool in 3 hours. when a third pipe is added and all three are used to fill the pool, it takes only 1 hour. find how long it takes the third pipe to do the job alone.

it's both, now can you answer my most recent question?

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