Sheila walks at the speed of her usual speed (20/21) and determines a clear distance in eight minutes more than the time it takes in normal speed. Calculate the normal time it takes to determine a certain distance.
Let the speed of the Sheila be 21 unit Speed of the Sheila after decrement = 21 x 20/21 = 20 unit Speed ratio = 21: 20 Time ratio = 20:21 ... [... Time taken is inversely proportional to speed] 21-21= 1 unit ATQ- 1 unit =8 min 20unit = 8 x 20 = 160 min The total time taken by Sheila at the usual speed was 160 min.