selecting a value using a conditional statement based on a list of tuples

I have a list of tuples converted from a dictionary. I am looking to compare a conditional value against the list of tuples(values) whether it is higher or lower starting from the beginning on the list. When this conditional value is lower than a tuple's(value) I want to use that specific tuple for further coding.

Please can somebody give me an insight into how this is achieved?

I am relatively new to coding, self-learning and I am not 100% sure the example would run but for the sake of demonstrating I have tried my best.

`tuple_list = [(12:00:00, £55.50), (13:00:00, £65.50), (14:00:00, £75.50), (15:00:00, £45.50), (16:00:00, £55.50)]

 conditional_value = £50

 if conditional_value != for x in tuple_list.values()
     y = 0
     if conditional_value < tuple_list(y)
         y++1
     else
         ///"return the relevant value from the tuple_list to use for further coding. I would be 
         looking to work with £45.50"///`

Thank you.