Office Market is having a sale on printer paper. If you buy 2 reams for $8.99 each, you will get a third ream free. Calculate the markdown percent. (Round the percent to the nearest tenth.)

for every 3 you buy, 1 of them is free.

so the "deal" is 1/3 off, or 33.333333% off, rounding to the nearest tenth 33.3%

just like "half-off" is 50% off, which is the same as 2 for 1 (because for every 2 you buy you get 1 free, in other words you get half the goods free)