Q: Tatuya, Ivanna, and Dorothy took a quiz together. Tatuya scored twice as much as Ivanna, and Ivanna scored 3/5 times as many marks as Dorothy. If Dorothy scored 90 marks, calculate the average marks scored by the three.
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A: Since Dorothy scored 90 marks, and Ivanna scored 3/5 times as many marks, Ivanna scored 3/5*90 = <<90*3/5=54>>54 marks.
Together, Dorothy and Ivanna scored a total of 54+90 = <<54+90=144>>144 marks.
If Tayuta scored twice as many marks as Ivanna, she scored 2*54 = <<2*54=108>>108 marks.
The total marks the three scored altogether is 108+144 = <<108+144=252>>252 marks.
The average marks for the three are 252/3 = <<252/3=84>>84 marks. The answer is  84.
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