Mr. duc asked to set up 450 chairs in a large hall. Perry puts 20 chairs in each row. He has already set up 15 rows of chairs. How many chairs must he set up

Mr. duc asked to set up 450 chairs in a large hall. Perry puts 20 chairs in each row. He has already set up 15 rows of chairs

Each row consists of 20 chairs

He already set up 15 rows

So number of chairs he already set up = chairs in each row * number of rows

20 * 15 = 300

So, he already set up 300 chairs

Total chairs to set up is 450

Remaining chairs to set up = 450 - 300 = 150

So, 150 more chairs to set up