Question

Janaki goes to temple at the speed 45 km/h, and she reaches 5 minutes early. Next day she goes at the speed of 60 km/h, and he reaches 30 minutes early. Find the distance between her house and temple
1. 75 km 
2. 80 km 
3. 70 km 
4. 90 km 
5. None of these 

Answer 1

Correct Answer - Option 1 : 75 km 

Given:

When speed is 45 kmph reaches 5 min early

When speed is 60 kmph reaches 30 min early

Formula:

Speed = distance/time

Calculation:

Let the distance be 'x' km

Therefore time taken to cover 'x' km at 45 kmph = x/45​ hr

Time taken to cover 'x'km at 60 kmph = x/60​ hr

But it is given that the difference between two timings 

⇒ 30 - 5 = 25 min = 25/60​ hr = 5/12

⇒ x/45 ​– x/60 ​= 5/12

⇒ (60x − 45x)​/45 × 60 = 5/12​

⇒ 15x/​45 × 60 = 5/12

⇒ x = 5 × 45 × 60/12 × 15

⇒ x = 75 km 

∴ Distance between home and temple is 75 km.