Question 526617
Car 1.
d = r*t
d = 280 km
r = 40 km/hr
t = d/r
t = 280/40
t = 7 hr
.
Car 2.
t = 6 hr 40 min = 6 2/3 hr = 20/3 hr
d = 280 km
r = 280/(20/3) 
r = 280 * 3/20
r = 14*3
r = 42 km/hr
,
Done.