Question 572227
P(Blue or Red pen) = P(Blue pen) + P(Red pen)


P(Blue or Red pen) = (# of blue pens)/(# total) + (# of red pens)/(# total) 


P(Blue or Red pen) = (5)/(4+5+3) + (3)/(4+5+3) 


P(Blue or Red pen) = 5/12 + 3/12


P(Blue or Red pen) = 8/12


P(Blue or Red pen) = 2/3