Sunom had to type 80 pages per day to complete an assignment. He could type only 60 page per day and is left with 2000 pages to type in the last 20 days. for how many days has Sumon been typing?

প্রশ্নঃ Sunom had to type 80 pages per day to complete an assignment. He could type only 60 page per day and is left with 2000 pages to type in the last 20 days. for how many days has Sumon been typing?