Ethan read a total of 40 pages + 10 pages = <<40+10=50>>50 pages on Saturday.
On the next day, he read a total of 50 pages x 2 = <<50*2=100>>100 pages.
The total number of pages that Ethan had read is 50 pages + 100 pages = <<50+100=150>>150 pages.
Therefore, Ethan has 360 pages - 150 pages = <<360-150=210>>210 pages left to read.
#### 210