I do not know if I did this question correctly. Can you please help me figure out this question if I have done it wrong?

3. At a particular bus stop, busses arrive every 20 minutes. The length of time a commuter waits for a bus at this stop is a uniformly distributed random variable, B. (a) Sketch a well-labeled probability density graph of B. [2 marks] Height = 1 2 10 12 14 16 18 20 (b) What is the probability that a randomly selected commuter will spend more than seven minutes waiting for the bus? [1 mark] 20 = 0.35 P (x > 7 ) = ( 1- 0:35 ) x 1 = 0. 65