Harrison read 10 more than the assigned 25 pages so he read 10+25 = <<10+25=35>>35 pages
Pam read 15 more pages than Harrison's 35 pages so she read 15+35 = <<15+35=50>>50 pages
Sam read twice the amount of Pam's 50 pages so he read 2*50 = <<50*2=100>>100 pages
#### 100