120 students took a chemistry test. 22 scored a 90.55 scored an 80, 12 scored a
70, 11 scored a 60, and 20 scored a 50. calculate the weighted average of the test
scores.

The weighted average of test score is 74.

Explanation:

Formula:

X = ∑xw/ ∑w

w                   x                          xw

22                90                         1980

55                80                         4400

12                 70                          840

11                  60                          660

20                50                         1000

∑w = 120                                 ∑xw = 8880

X = ∑xw/ ∑w

X =  8880/ 120

X= 74

the answer is definitely c.

i'm pretty sure its b i might be wrong though!