Question

A boy covers a distance of 2.5 km in 15 minutes and the next 3 km in 18 minutes. What is the average speed of the boy?
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Answer 1

Answer:

Distance covered by a boy = 2.5 km

Time taken = 15 minutes

Next distance covered by the boy = 3 km

Time taken = 18 minutes

Average speed

$= ) \: \frac{total \: distance \: covered}{total \: time \: taken} \\ = ) \: \frac{2.5 + 3}{ \frac{15}{60} + \frac{18}{60} } \\ = ) \: \frac{5.5}{ \frac{11}{20} } \\ = ) \: \frac{ \frac{11}{2} }{ \frac{11}{20} } \\ = ) \: \frac{11}{2} \times \frac{20}{11} \\ = ) \: 10 \: km \: per \: hour$

The average speed of the boy is 10 km/hr.

Answer 2

Speed = Distance/Time

2.5 km + 3 km = 5.5 km

5.5 km = 550 m

15 min + 18 min = 33 min

33 min = 1,980 sec

Speed = 550 / 1,980

Speed = 275m / 99s

( 2.77 m/s )