A student walks from his house at a speed of 2.5
A student walks from his house at a speed of 2.5 km/h and reaches his school 6 min late. The next day he increases his speed by 1 km/h and reaches 6 min before school time. How far is the school from his house?
A$$\frac{5}{4} km$$
B$$\frac{7}{4} km $$
C$$\frac{9}{4}km$$
D$$\frac{11}{4}km$$
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Answer is \(\frac{7}{4} km\)
Explanation:
Let the distance be x km
\(\text{Distance in timings =12 min =}\frac{12}{60}\text{ hr}=\frac{1}{5} \text{hr} \)
\(\therefore \frac{2x}{5}-\frac{2x}{7}=\frac{1}{5} \)
\(14x-10x=7\)
\(x = 1\frac{3}{4}\text{ km}\)
\(x= \frac{7}{4}\text{ km}\)
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