A person crosses a 1600 m long street in 4 min. What is his speed (in km/h)?

Options:
a) 22
b) 14
c) 20
d) 24

Solution:

Distance = speed x time
as per questions
distance = 1600m =1.6km
Time = 4 min.=4/60 hr.
Speed =?

speed =$ \frac {d}{t} =\dfrac{1.6}{\frac{4}{60}}$
speed =$ \frac{1.6\times60}{4}$
speed =24 km/h

Ans: 24 km/h