The second one (9.5, 9 3/4, 9 3/8, 9.125)
Answer:
Refractive index of a medium depends upon the refractive index of the surroundings
East= 45 x 22 = 990 students
west= 42 x 23 = 996 students
996 - 990 = 6 students
990 - 996 = -6 students
There are 6 more students at West school than East school. There are -6 more students at East school than West school.
Hope it helps!