Initially a shopkeeper had ldquo x rdquo pens A customer bought 10 of pens from ldquo x rdquo then a...........

Initially, a shopkeeper had “x” pens. A customer bought 10% of pens from “x” then another customer bought 20% of the remaining pens after that one more customer purchased 25% of the remaining pens. Finally, shopkeeper is left with 270 pens in his shop. How many pens were there initially in his shop?