Answer:
It would cost ( 3xr/200) dollars  to three people to travel x miles.
Step-by-step explanation:
Here, according to the question:
The rate of the taxi fare = r cents per person per mile
The total number of people travelling = 3 friends
Each person travels x miles.
So, the total distance traveled by 3 friends
= 3 Â ( Distance traveled by 1 friend) = (3 x) miles
Now, as each mile costs r cents.
So, the cost of travelling (3 x) miles  = ( 3 x) (r)  cents  .... (1)
Also, 100 cents = $ 1
So, Â 1 cent = (1/100) dollars
⇒ r cents  = (r/100) dollars
So, the cost of travelling (3 x) miles  = ( 3xr/100) dollars  .... (2)
Now, If he gives them a 50% DISCOUNT.
Then the cost of travelling (3 x) miles  = ( 3xr/ 2 x 100) dollars Â
= ( 3xr/200) dollars Â
Hence,it would cost ( 3xr/200) dollars  to three people to travel x miles.