SOLUTION: For how long does a 24-hour digital watch display at least one digit which is 5 from 2:05 to 5:55? A)1hr 45 min B)1 hr 41 min C)1 hour 40 min D)55 min E) 45 min

Algebra ->  Percentages: Solvers, Trainers, Word Problems and pie charts -> SOLUTION: For how long does a 24-hour digital watch display at least one digit which is 5 from 2:05 to 5:55? A)1hr 45 min B)1 hr 41 min C)1 hour 40 min D)55 min E) 45 min      Log On


   

Question 626439: For how long does a 24-hour digital watch display at least one digit which is
5 from 2:05 to 5:55?
A)1hr 45 min
B)1 hr 41 min
C)1 hour 40 min
D)55 min
E) 45 min
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
During the hours 2:05 to 2:59, 3:05 to 3:59, and 4:05 to 4:59 there are 

1. minutes :05, :15, :25, :35, :45 amounting to 5 separate minutes
2. minutes :50 through :59 amounting to 10 continuous minutes

So during each of those three hours, at least one 5 is displayed 15 
minutes,  So that accounts for 45 minutes.

From 5:00 THROUGH 5:55 is 56 continuous minutes.

Therefore a 5 is displayed 45+56 = 101 minutes = 1 hour 41 minutes
THROUGH the minute from 5:55 to 5:56.

However the problem states TO 5:55, not THROUGH.  So I guess that means 
only through 5:54, then the answer is 1 hour 40 minutes. 

Edwin