Question

Rahul went to meet his sister in a nearby district. While going, he covered one third of the distance at an
average speed of 12 km/h and two third at an average speed of 18 km/h. During the return journey his average
speed was 36 km/h. If he spent total 10 hours in his total journey, excluding the time of stay, the total
distance of his sister's house from the starting point is -

1. 95km
2. 108km
3. 103km
4.115km​

Answer 1

Answer:

I think correct answer will option 1 95km

Answer 2

Given : Rahul went to meet his sister in a nearby district. While going, he covered one third of the distance at an  average speed of 12 km/h and two third at an average speed of 18 km/h. During the return journey his average  speed was 36 km/h.

he spent total 10 hours in his total journey, excluding the time of stay

To Find : the total  distance of his sister's house from the starting point is -

1. 95km

2. 108km

3. 103km

4.115km​

Solution:

Let say Distance of house = 3D km

one third Distance = D km

Speed = 12 km/hr

Time = D/12  hr

two third Distance = 2D km

Speed = 18 km/hr

Time = 2D/18 = D/9  hr

During the return journey his average  speed was 36 km/h.

Time = 3D/36  = D/12

D/12 + D/9  + D/12   = 10

=> 3D + 4D + 3D  = 360

=> 10D = 360

=> D = 36

=> 3D = 108

the total  distance of his sister's house from the starting point is -= 108 km

option 2 is correct

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