-- 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 ?