Ruby testing with rspec

Hello im trying to run a few specifications using RSpec. On my computer
i have installed rspec 2.99 and 3.2.3 as well as rspec core 2.99 and
rspec
core 3.2.3 my terminal is telling me that jam using rspec core,mocks and
expectations 2.99 can anyone please tell me the command i have to enter
to use rspec core,mocks and expectations 3.2.3

thank you so much