It may last a little while longer. FYI, those Ritalin tablets have some nasty binders and fillers in them. You are introducing binders and fillers that are not water soluble. In other words, there is shit in that what you snort that will never leave your system. I'm not trying to preach, but those tabs are nasty for snorting. I recommend either crushing a lot of them up and parachuting them, or getting a syringe from the drug store and shooting that stuff up your ass. You will get rushes and high by doing what I suggested. If you have to snort, go get some coke.
Most of the time snorting will give you a higher peak and shorter duration.