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How many distinct sets of three positive integers have a mean of 6, a median of 7, and nomode? |
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Answer» Given mean=6, median=7, no mode Let the three positive integers be x, x+1, x+2 Now mean = (x+x+1+x+2)/3 = (3x+3)/3 = x+1 But here x+1=6 i.e., x=5 ... which means we have 5 sets of numbers whose mean is 6. (But this is just for knowing the number of sets, we can't use it further) , and also from definition of mean Mean= sum/ total number of integers... i.e., we get that sum= mean*total no. Of integers = 6*3=18 As median given is 7 and we have only 3 intergers in the set .. we can know that middle number is 7 ..i.e., the number set is : 0+7+11=18 1+7+10=18 2+7+9=18 3+7+8=18 5+7+6=18 As there is no mode we cant get the set (4+7+7) |
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