Lowella got 100 x 35/100 = <<100*35/100=35>>35 correct answers.
Pamela got 35 x 20/100 = <<35*20/100=7>>7 more correct answers than Lowella.
So, Pamela got 35 + 7 = <<35+7=42>>42 correct answers.
Thus, Mandy got 42 x 2 = <<42*2=84>>84 correct answers.
#### 84