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By walking at the rate of 4 km per hour, I reach my destination 15 minutes too late and I reach 20 minutes too soon by walking at 6 km/hr. How far have I to walk ?
- A8 km
- B6 km
- C\(4\frac{1}{2}km\)
- D5 km
Answer not set
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CCommunity
Let the destination is ‘x’ km away from the point person is walking
If the person walks at 6 km per hour he is 20 minutes early and 15 minutes late if he walks 4 km per hour. So, it makes a difference of (15 + 20) = 35 minutes = 35/60 hourTime taken to cover distance ‘x’ at 4 km/hr = x/4 hrs
Time taken to cover distance ‘x’ at 6 km/hr = x/6 hrs.
$(\begin{array}{l} \therefore \frac{x}{4} - \frac{x}{6} = \frac{{35}}{{60}}\\ \Rightarrow \frac{{15x}}{{60}} - \frac{{10x}}{{60}} = \frac{{35}}{{60}}\\ \Rightarrow \frac{{5x}}{{60}} = \frac{{35}}{{60}} \end{array})$
⇒ x = 7 km
If the person walks at 6 km per hour he is 20 minutes early and 15 minutes late if he walks 4 km per hour. So, it makes a difference of (15 + 20) = 35 minutes = 35/60 hourTime taken to cover distance ‘x’ at 4 km/hr = x/4 hrs
Time taken to cover distance ‘x’ at 6 km/hr = x/6 hrs.
$(\begin{array}{l} \therefore \frac{x}{4} - \frac{x}{6} = \frac{{35}}{{60}}\\ \Rightarrow \frac{{15x}}{{60}} - \frac{{10x}}{{60}} = \frac{{35}}{{60}}\\ \Rightarrow \frac{{5x}}{{60}} = \frac{{35}}{{60}} \end{array})$
⇒ x = 7 km