the question is

Let W ~ Uniform [1,4]. Compute:

P(W>=5)

the book says from the intro (not the answer)

P(a<=x<=b) = b-a / R - L

so using this i get

inf - 5 / 4 - 1

so inf / 3

so inf = P(W>=5)

but this doesn't make sense to me...

What am i doing wrong?