cheryl and judy trudged at 4 miles per hour then continued a

cheryl and judy trudged at 4 miles per hour then continued at brisk pace of 6 miles per hour. If the total trip of 56 miles took 12 hours, how long did they trudged and how long did they walk briskly?

Solution

Let time taken for trudging be t hours
then time they walked at a brisk pace = 12 - t
Distance traveled = speed * time
4t + 6(12 - t) = 56
4t + 72 - 6t = 56
-2t = 56 - 72
-2t = -16
t = 8 hours
Time taken for trudging = 8 hours
Time they walked briskly = 4 hours