Nobody seems to measure or count anymore , with out a phone app to do it for them ..
I'd say look at the pictures * and look at yours
Notice only the 50t one has an extra 10 holes in the arms of the chainring,
*
http://www.sjscycles.co.uk/brompton-...&page=1&page=1
Cue the sesame street song "which one of these is not like the other one" ..
