Question

Normally sarita takes 3 hours to travel between two stations with constant speed. One day her speed was reduced by 12 km/h and she took 75 min more to Complete the journey then distance between the two stations is

a. 60km
b. 120km
c. 180km
d. 95km

Answer 1

Given,

Normal time to complete journey = 3 hours

Speed reduced = 12 km/h

Time increased = 75 min

To find,

Distance between two stations.

Solution,

We can simply solve this mathematical problem by using the following mathematical process.

Let, the total distance = x km

The initial speed = y km/h

Initial time = 3 hr

Final time = 3hr +75 min = 3hr + 60min + 15min = 4.25 hr

according to the data mentioned in the question,

x/y = 3

x = 3y....(1)

And,

x/(y-12) = 4.25

x = 4.25y - 51....(2)

Now, comparing (1) and (2),

3y = 4.25y - 51

4.25y-3y = 51

1.25y = 51

y = 40.8

Putting the value of y into (1)

x/40.8 = 3

x = 122.4

Hence, the total journey distance is 122.4 km