The bench costs $450.
You first need to subtract the difference between the garden table and the bench from the total so they are equivalent, and then divide by two to find what the bench is on its own.
(The garden table costs $536, by the way. To find that, you just need to add its half of 900, 450, to the 86 you subtracted initially.)
Tell me if this doesn’t make sense, it’s sort of hard to explain!
