.25(k-1)=10

Solution for .25(k-1)=10 equation:

Simplifying
0.25(k + -1) = 10

Reorder the terms:
0.25(-1 + k) = 10
(-1 * 0.25 + k * 0.25) = 10
(-0.25 + 0.25k) = 10

Solving
-0.25 + 0.25k = 10

Solving for variable 'k'.

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

Add '0.25' to each side of the equation.
-0.25 + 0.25 + 0.25k = 10 + 0.25

Combine like terms: -0.25 + 0.25 = 0.00
0.00 + 0.25k = 10 + 0.25
0.25k = 10 + 0.25

Combine like terms: 10 + 0.25 = 10.25
0.25k = 10.25

Divide each side by '0.25'.
k = 41

Simplifying
k = 41