Question

A man takes 30 minutes to cover a certain distance at the speed of 3 km/hr . By how much should he increase his speed to cover the distance in 20 minutes?​

Answer 1

Answer:

1.5 speed increase

Explanation:

(3+x)×20=3×30

60+20x=90

20x=30

x=1.5

Answer 2

Answer:

the distance covered in 30 min =1/2h at the speed of 3km/h is

D=S×T =3km/h ×1/2h =3/2km

the required speed to cover 3/2km in 20 min =1/3h is

T=D/S 3/2km /1/3h=

3×3/1×2=9/2=4.5km/h

4.5-3 = 1.5 km/h