Answer :
60 times 2.8 = 168 videos watched in total
40 times 3.3 = 132 videos watched by boys
168 -132 = 36 videos watched by girls
36 / 20 = 1.8
40 times 3.3 = 132 videos watched by boys
168 -132 = 36 videos watched by girls
36 / 20 = 1.8