If Anjali walks to her office at a speed of 4 km/hr, she reaches her office 8 minutes before the school time

Question

If Anjali walks to her office at a speed of 4 km/hr, she reaches her office 8 minutes before the school time., If she walks at 3km/hr she reaches the office 7 minutes late. Find the distance from her house to office.

Answer 1

For this, we will want to use the fact that Distance = Rate * Time

 

In both situations, Anjali is walking the same distance, so Rate * Time for the first trial has to be equal to Rate * Time for the second trial.  

 

Trial 1:  Rate = 4 km/hr

Trial 2:  Rate = 3 km/hr

 

And we know that Trial 2 takes 15 minutes (7 min + 8 min), or .25 hours, longer than Trial 1.

 

(4 km/hr)(T hrs) = (3 km/hr)(T + .25 hrs)

4T = 3T + .75

T = .75 hours

 

Now we can back-solve for the distance:

 

Distance = Rate * Time = (4 km/hr)(.75 hrs) = 3 km

 

Similarly, we can back-solve into the other trial (since they are equal):

 

Distance = Rate * Time = (3 km/hr)(.75 + .25 hrs) = 3 km

 

J.T.