Bruno's hourly salary is 6.75. last week he worked a 20 hour week. how much did he earn

6.75*20=135. He earned $135. 

Simple equation should do the trick.

Bruno makes 6.75 per hour that can be represented by the following; h being the variable for "hours" hence, the h.

6.75h
Las week he worked 20 hours,  so plug that in for h

Like so ;

6.75(20) = How much $ Bruno made
135 = how much $ Bruno made

So Bruno made 135$ last week.