.
Your system of equation is
m + f = 65, (1)
f =
+ 5. (2)
To rid of the denominator, multiply (2) by 5 (both sides).
Then you get your system in the form
m + f = 65, (1')
5f = m + 25. (2')
Can you solve it on your own?
Use the substitution method.
Answer. 50 male, 15 females.