Answer :

You can set up a proportion to solve it.
6         15
------ =  ------
270       x

270*15=4050
4050/6=675.

So the answer is B.
If you do not understand pls tell me.
AL2006
 
-- According to the table, he earns $270 for 6 days' work.  If you divide
$270 by 6, you find that for 6 days' work, he earns $45 per day.

-- According to the table, he earns $360 for 8 days' work.  If you divide
$360 by 8, you find that for 8 days' work, he earns $45 per day.

-- According to the table, he earns $540 for 12 days' work.  If you divide
$540 by 12, you find that for 12 days' work, he earns $45 per day.

-- Apparently, it doesn't matter how many days he works.  He always
earns $45 for each day.

Does that help you finish the problem on your own ?