Answers

2016-03-23T20:43:46+05:30
Class mark= (upper limit+ lower limit)/2 So class mark=11+20/2 =31/2=15.5 So 15.5 is the class mark Hope it helps
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2016-03-23T21:10:58+05:30
Class mark is upper limit + lower limit / 2 So...the second class interval is 11-20...20 is d upper limit n 11 is d lower limit...thus (20 + 11) /2 Therefore 31/2..thus 15.5 is d class mark......
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