A girl reduced his speed to 4/7th and reaches her destination in 14 hours . If she had walked at her initial speed then how much time had she saved ?

6 hours

Ratio                            old     :      new

Speed                          7        :        4

Time                            4         :       7

According to question , 7R = 14 hours

                                  1R = 2 hours

    time saved if she walked by his usual speed is ,

                                 3R  =  6 hours