Simplify.
3n + 2n = 5n
5n - 5p = 10p
Isolate the n. Note the equal sign. What you do to one side, you do to the other. Do the opposite of PEMDAS. First, add 5p to both sides
5n - 5p (+5p) = 10p (+5p)
5n = 15p
Next, divide 5 from both sides
5n/5 = 15p/5
n = 15p/5
n = 3p
3p is your answer for n
hope this helps