Define some variables.

Let a represent the revenue due to advertising.

Let s represent the revenue due to subscription.

You are told that together, they amount to 68 million.

So,

a + s = 68

Then, you are told that advertising was 6 times bigger than subscription.

a = 6s

You get two equations with two unknowns. Solve for a, the earning from magazine.

Post what you get!