Hi Coudjo,

Problems like this can be sneaky in the sense that there's hidden information that we have to look for.  Let's start from the beginning and write down everything we know as we go.

So it starts by telling us that Oliver charges $10 for every lawn he mows.  Skipping ahead a bit it tells us that he made $265 in one week, so right now we have 10r = 265.  The question then tells us that he charges $5 more for every large lawn he mows.  This means that the price of 1 large yard is the flat rate $10, plus the $5 for the lawn being large.  Meaning that for every large yard he mows, it costs $15.  So, now we have 10r + 15L = 265.  I created L to represent the number of large yards he mowed.  However, the question then tells us he mowed 6 more large lawns than he did regular lawns, so L now means (r + 6).  Now we have 10r + 15(r + 6) = 265, and that is answer C.

Hopefully that was less confusing than the explanation from the question.  If you're still confused about anything, please let me know.

Elijah

Thank you Elijah. Your explanation is much more clearer. I'm Ok now.