Chad sold 30 magazine subscriptions.
Given, Rebecca sold 11 more magazines subscriptions than chad.
Let the number of magazines sold by chad be "n", then number of magazine sold by Rebecca will be "n + 11"
Given that Laura sold 4 more than Rebecca.
Then, number of magazines sold by Laura will be 4 + n + 11 ⇒ n + 15
Total magazine sold by Laura = 45
Total magazine sold by Chad = ?
Total magazine sold by Laura = n + 15 = 45
n = 45 – 15 = 30
Since "n" indicates number of magazine sold by Chad. Thus n = 30 means that Chad sold 30 magazine
so far i think you have the right thing going for you just remember soh cah toh
sine over hypotenuse
cosine equals adjacent
tangent over hypotenuse