What does the expression 0.90(d – 5) refer to? How do you know? How else
could this expression be written?
The expression 0.90(d - 5) refers to 90% of the quantity (d - 5).
We know this because the expression starts with 0.90, which is equivalent to 90% or 90/100. It also multiplies this percentage by the quantity (d - 5), which means we are calculating 90% of (d - 5).
This expression could be written as 0.9d - 4.5.