The value of varies directly with x. when y = 7.5 , x = 5. what is the value of y when x = 80?

you can first factor out the n to get n(1+5). we know that 1+5 is 6, so we just have 6n.

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

multiplication is multiplication.   it might feel harder depending on what level of math you are in, but generally it will be the same old stuff, while implementing some new concepts and methods of solving work.