p(xis less than or = 3) = area of the triangle with base [1,3] and height =1/2 =1/2*2*1/2=1/2
the triangle with base [1,2] is similar to triangle with base [1,3]
so aria of triangle with base [1,2] =1/8
p(x is between1 and 2)=1/8
p(x>5) = 0
p(x>2) =1 -1/8 =7/8

 

 

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