A train running at$\frac{\text{7}}{12}$  of  its own speed reached a place in 24 hrs. How much time could be saved if the train would have run at its own speed ?        

Ratio of  speed = 12 : 7

Ratio  of  time = 7 : 12

Given 12 units = 24 hrs

1 unit = 2 hrs

Actual time i.e$7units=7\times 2=14hrs$

$totaltimesaved=24hrs-14hrs$

$Savedtime=10hrs$