50=.4*n

Solution for 50=.4*n equation:

Simplifying
50 = 0.4n

Solving
50 = 0.4n

Solving for variable 'n'.

Move all terms containing n to the left, all other terms to the right.

Add '-0.4n' to each side of the equation.
50 + -0.4n = 0.4n + -0.4n

Combine like terms: 0.4n + -0.4n = 0.0
50 + -0.4n = 0.0

Add '-50' to each side of the equation.
50 + -50 + -0.4n = 0.0 + -50

Combine like terms: 50 + -50 = 0
0 + -0.4n = 0.0 + -50
-0.4n = 0.0 + -50

Combine like terms: 0.0 + -50 = -50
-0.4n = -50

Divide each side by '-0.4'.
n = 125

Simplifying
n = 125