Answer:
Step-by-step explanation:
From the information given:
the rate of the cars = 
the rate of the buses = 
the rate of motorcycle = 
The probability of any event at a given time t can be expressed as:

∴
(a)






Thus;
P(exactly 2 cars, 1 motorcycle in 20 minutes) = 0.1465 × 0.3422 × 0.1353
P(exactly 2 cars, 1 motorcycle in 20 minutes) = 0.0068
(b)
the rate of the total vehicles = 0.2 + 0.1 + 0.0333 = 0.3333
the rate of vehicles with exact change = rate of total vehicles × P(exact change)

= 0.0833
∴

P(zero exact change in 10 minutes) = 0.4347
c)
The probability of the 7th motorcycle after the arrival of the third motorcycle is:


Thus; the probability of the 7th motorcycle after the arrival of the third one is = 0.0469
d)
P(at least one other vehicle arrives between 3rd and 4th car arrival)
= 1 - P(no other vehicle arrives between 3rd and 4th car arrival)
The 3rd car arrives at 15 minutes
The 4th car arrives at 20 minutes
The interval between the two = 5 minutes
<u>For Bus:</u>
P(no other vehicle other vehicle arrives within 5 minutes is)
= 
<u>For motorcycle:</u>

∴
The required probability = 
= 1- 0.5134
= 0.4866