7. A bus covers a certain distance in 60 minutes if it runs at a speed of 60 km/hr. What must be the speed of the bus in order to reduce the time of journey by 40
minutes?

90 Km/h

Explanation:

60 mins is 1 hr

so in an hour bus covers 60 Km

so new speed:

d/t

(60km/40mins)*60mins/h

90Km/h

b.transmitters send radio waves, and receivers capture radio waves.

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day