How do you work this problem?

The value of a Nebraska state coin (uncirculated) is 8/7 the value of a (uncirculated) Philadelphia state coin.Together the total value of the two coins is $15.00.What is the value of each coin?How do you work this problem?
say that n stands for nebraska's coin and p stands for philly's. we know that:


n = 8/7p


and that:


n + p = $15





substitute 8/7p for n in the second equation:


8/7p + p = 15


15/7p = 15


p = $7





plug p = 7 into the first equation to solve for n:


n = 8/7(7) = $8





hope that helps!How do you work this problem?
N = 8/7 P


P + N = $15


Therefore, P + 8/7 P = $15


15/7 P = 15


P = $7


$7 + N = $15


N = $8