What does the 3 represent in 3 (20 15) ?

Depending on what you're supposed to do, the three could either mean to distribute it into the equation, giving you

either

(3*2015) or (3*20) * (3*15) or (3*20) + / - (3*15)

Or an example of factoring where they took 3 out of 60 and 45.

There are no instruction on what to do in this question.