 
 <translate> If she had 400 papers, the total number of documents she separated as invalid is 40 / 100 * 400 pages = 160 pages. The number of valid documents is 400 pages - 160 pages = 240 pages.
The final answer: 240. <hau> Idan tana da takardu 400, jimlar takardun da ta ware a matsayin marasa inganci shine 40 / 100 * 400 shafuka = shafuka 160. Adadin ingantattun takardu shine shafuka 400 - shafuka 160 = shafuka 240. Amsar ƙarshe ita ce: 240. 