Step-by-step explanation:
Let x = distance from house after some time has passed
distance = rate * time
Let time = t
Alan is 6-x miles away when he meets Soren
6-x = 7t
t = (6-x)/7
Soren is 8-x miles away when he meets Alan
8-x = 12t
t = (8-x)/12
The two will have travelled the same amount of time when they meet since we are assuming they left at the same time.
(8-x)/12 = (6-x)/7
7(8-x) = 12(6-x)
56 -7x = 72 - 12x
5x = 16
x = 16/5 = 3.2 miles traveled when they meet
You can plug in (16/5) for x in one of the earlier equations to get the time.
t = (6-(16/5))/7
= ((30/5)-(16/5))/7
= (14/5)/7
= (14/5) × (1/7)
= 14/35
= 2/5 = 0.4 hours