Does anyone know the answer for this?

He bought (a.) 4 packages of batteries. He returned the defective tape recorder for a store credit of $45 dollars. We know that he received $33 in refund, so the amount of money he spent on batteries is his store credit minus the refund ($45-$33), which is $12. Each package of batteries costs $3, so the amount of packages he bought can be found by dividing the money he spent by the cost per package, or $12/$3, which is equal to 4 packages.