9+8 is the commutative property
1. the last one
2.the first one hope this helps.
Since the buses travel in opposite directions, the speed at which they distance themselves is the sum of their speeds.
One bus travels at speed s.
The other bus travels at speed s + 15.
The sum of the speeds is s + s + 15 = 2s + 15
speed = distance/time
distance = speed * time
366 = (2s + 15) * 2
183 = 2s + 15
168 = 2s
s = 84
The slower bus travels at 84 km/h.
s + 15 = 84 + 15 = 99
The faster bus travels at 99 km/h.
Check:
In 2 hours, the slower bus travels 2 * 84 km = 168 km
In 2 hours, the faster bus travels 2 * 99 km = 198 km
In 2 hours, the buses are 198 km + 168 km = 366 km apart.
Our answer is correct.
