Question

The base fare (B) covers the first mile or less, and only the distance travelled after one mile is charged. For example, if the distance travelled is D = 6.5 miles, then the total fare is given as T = B + P * (6.5 – 1). Use Python to write a program to take as input the prevailing rate P and the distance travelled D, and output the total fare (T) for the given trip. For this program you should assume that the base fare (B) is £4.70.

The program should check that the input value for the prevailing rate (P) is positive and, if not, give the error message ‘The prevailing rate must be positive’. It should also check that the distance travelled (D) is positive and, if not, give the error message ‘Distance travelled should be positive’. In both cases, the user should then be prompted to input the value again until it is positive.

Create and test your program in the following Python environment. You may include comments in the program to make it clearer.

Answer 1

We have to keep taking the input from the user until we get a positive value for both the prevailing rate (P) and the distance travelled (D). We can use a while loop and a flag variable for this operation.

If we get both inputs to be positive, we set the value of flag to be False and we break out of the while loop.

Now, we store the values of P and D in float variables. We have been given the value of the base fare B as 4.70.

Now, it's simply a matter of plugging in the values into the equation and get the result.

Here's the code.

flag = True;

while(flag == True):
P = float(input('Enter the prevailing rate : \n'))
  
if(P < 0):
print('The prevailing rate must be positive')
continue
  
D = float(input('Enter the distance travelled : \n'))
  
if(D < 0):
print('The distance travelled must be positive.')
continue
  
flag = False

base_fare = 4.7

total_fare = base_fare + P * (D - 1)

print('The total fare for the entire trip is ' , total_fare)

Also attached are the screenshots of the code and the output for the given input.

flag = True; while(flag == True): P = float(input('Enter the prevailing rate : \n')) if(P < ): print('The prevailing rate must be positive') continue D = float(input('Enter the distance travelled : \n') if(D < 0): print('The distance travelled must be positive.') continue flag = False base_fare = 4.7 total_fare = base_fare + P * (D - 1) print('The total fare for the entire trip is ', total_fare)

Input 6.5 Output Enter the prevailing rate : Enter the distance travelled : The total fare for the entire trip is 37.7

Let me know if you have any doubts in the comments. Please upvote if the answer helped you.