To have 30 bulbs, Maura can buy 10 packages of 3 at $5.37 each, for a total of $53.70. Or, she can buy 15 packages of 2 at $4.52 each, for a total of $67.80.
Buying in packages of 3, Maura saves $67.80 -53.70 = $14.10.
Yes, it is an equivalent expression because even though you move two pieces of an equation it will still equal the same thing, unless there are parentheses involved.
