I believe answer is any real number
so
<span>D.
x can be any real number</span>
The original price was £320 before the 40% sale price
The first blank is proportional because <span>two quantities is one in which the two quantities vary directly with one and other. </span>If<span> one item is doubled, the other, related item is also doubled. Because of this, it is also called a direct variation. </span>
