Dan has 20 books in his library. He bought several books at a yard sale over the weekend. He now has 71 books in his library. How many books did he buy at the yard sale?
Mathematics · High School · Tue Nov 03 2020
Answered on
To find how many books Dan bought at the yard sale, let x be the number of books he bought at the yard sale. Since Dan already has 20 books in his library and now after he brought books from the yard sale he has 71 book, the problem can be written as 20 + x = 71.
To solve for x, subtract both sides by 20.
> 20 + x = 71
> 20 + x- 20 = 71- 20
> x= 51.
Dan brought 51 books at the yard sale.