300=400*5*r

Solution for 300=400*5*r equation:

Simplifying
300 = 400 * 5r

Multiply 400 * 5
300 = 2000r

Solving
300 = 2000r

Solving for variable 'r'.

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

Add '-2000r' to each side of the equation.
300 + -2000r = 2000r + -2000r

Combine like terms: 2000r + -2000r = 0
300 + -2000r = 0

Add '-300' to each side of the equation.
300 + -300 + -2000r = 0 + -300

Combine like terms: 300 + -300 = 0
0 + -2000r = 0 + -300
-2000r = 0 + -300

Combine like terms: 0 + -300 = -300
-2000r = -300

Divide each side by '-2000'.
r = 0.15

Simplifying
r = 0.15