Question

A class sorted 45 books in 90 minutes. How long would it take to sort 120 books?

Answer 1

$45 \ books\ in\ 90\ minutes\\\\ 120\ bookes\ in\ x\ minutes\\\\ making\ proportion\\ 45-90\\120-x\\\\cross\ multiplication\\\\ 45x=90*120\\\\ 45x=10800\ \ \ | divide\ by\ 45\\\\x=240\\\\ It\ will\ take\ 240\ minutes.$

Answer 2

45 * 2 2/3 = 120
90 * 2 2/3 =240
It would take 240 minutes to sort 120 books