The hardcover version of a book sells for 15 dollars and the paperback sells for 11.50. If a store sells 70 copies of the book in one month and charges 917 dollars how many hardcover versions were sold
Mathematics · High School · Tue Nov 03 2020
llm
Answered on
Let number of hardcover books be X
And, number of paperback books be y
Then,
x + y = 70 ….1
15x + 11.50y = 917 ….2
From equation 1
y = 70 - x
Putting value of y in equation 2, we get
15x + 11.50(70-x) = 917
15x + 805 - 11.50x = 917
3.50x = 917 - 805
3.50x = 112
x = 112/3.50
x = 32
Thus, 32 hardcover version were sold.