I did it this way: 100x return is 800M, 200x return is 1.6B, so 16B is 2000X return, which is 200,000% return in initial investment.
I think it's less than that though, since obviously Sequoia didn't get 100% of the company for their 8M, I think they walked away with 2.4B after this deal?
Whatsapp raised another 50m from Sequoia after those initial 8m