A Recent Study Used Videotapes of Eighth-Grade Math Classrooms to Examine

A recent study used videotapes of eighth-grade math classrooms to examine how math is taught in different countries. The study showed that Japanese teachers let students spend _______ minutes on average struggling to solve a math problem compared to only ______ minutes on average for U.S. teachers.

A) 21; 5
B) 20; 2
C) 15; 5
D) 5; 15