We can rewrite the two equations, using the rules of logs, as follows:
log P - log N = 5 .........(1)
log M - log N = 4 .........(2)
Subtracting equation (2) from equation (1) gives:
log P - log M = 1 ........(3)
Equation (3) can be written as:
\(log\frac{P}{M}=1\)
Therefore
\(\frac{P}{M}=10\)
