Question 119273
Using your equation:
n+8/7n=15 [combine like terms]
7/7n+ 8/7n=15  
15/7n=15 [solve for the n-term]
(7/15)(15/7)n=(15/1)(7/15)
n=7
So, the Phil coin = n = 7
and the Denver coin = 8/7n=(8/7)(7/1)=8
.
checking:
7+8=15
15=15 [checks out]