Answer:
Tina's average speed for the whole journey = 56 kmph
Step-by-step explanation:
Time taken by Sean to travel from Town A to Town B = 4 hours.
Average speed of Sean = 70 km/h
We have equation of motion, s = ut + 0.5 at²
Time, t = 4 hours.
Initial speed, u = 70 km/hr
Acceleration, a = 0 m/s²
Substituting
s = ut + 0.5 at²
s = 70 x 4 + 0.5 x 0 x 4²
s = 280 km
Distance from Town A to Town B = 280 km
Tina took 1 hour more than Sean.
Time taken by Tina to travel from Town A to Town B = 4 +1 = 5 hours
We have equation of motion, s = ut + 0.5 at²
Time, t = 5 hours.
Displacement, s = 280 km
Acceleration, a = 0 m/s²
Substituting
s = ut + 0.5 at²
280 = u x 5 + 0.5 x 0 x 5²
u = 56 km/hr
Tina's average speed for the whole journey = 56 kmph
