Question

Shelf A had 40 books and Shelf B had 16 books. After Katrina borrowed an equal number of books from Shelf A and Shelf B, there were 3 times as many books on Shelf A than Shelf B. How many books did Katrina borrow altogether?

Answer 1

8 books; 4 from each shelf

Explanation:

let x represent equal number of books from each shelf

from shelf A = 40 -x

from shelf B = 16 -x

shelf A has 3 times as many books than shelf B

3(16- x) = 40 -x

48 -3x = 40 -x

48 - 40 = -x + 3x

8 = 2x

x = 4

altogether she borrowed 4 + 4 = 8 books