Since the waiting times are uniformly distributed between 0 and 7 minutes, the probability density function (PDF) of the waiting time is:
f(x) = 1/7 for 0 ≤ x ≤ 7
0 otherwise
To find the probability that the waiting time is less than 0.75 minutes, we need to integrate the PDF from 0 to 0.75:
P(X < 0.75) = ∫[0,0.75] f(x) dx
P(X < 0.75) = ∫[0,0.75] 1/7 dx
P(X < 0.75) = [1/7 * x] [0,0.75]
P(X < 0.75) = 1/7 * 0.75
P(X < 0.75) = 0.1071
Therefore, the probability that the waiting time is less than 0.75 minutes is 0.1071 (rounded to three decimal places).