Of 200 students who attended class, half wore colored lipstick, or 200/2=<<200/2=100>>100 students wore colored lipstick.
Of those students who wore lipstick, one quarter wore red lipstick, or 100/4=<<100/4=25>>25 students wore red lipstick.
Since there were one-fifth as many students wearing blue lipstick as were wearing red lipstick, then 25/5=<<25/5=5>>5 students wore blue lipstick.
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