Agarden table and a bench cost $600 combined. the cost of the garden table is three times the cost of the bench. what is the cost of the bench?

This is how I'd solve it:

bench = x           x+3x=600 
table = 3x               4x=600
                                 x=150

The bench costs $150 and the table costs $450; combined, they cost $600, so it's correct. I hope this helps you!