Question 992205
Assign variables this way:
{{{system(L=22,w=6,u=unknownUniformWidthofWalkway,A=245)}}}


{{{(L+2u)(w+2u)-wL=A}}}, the difference between the pool area and the combined pool & walkway area leaves just the walkway area, which is given.  Solve for the unknown variable, u.



If you find no trouble solving that equation for u, or at least carrying many of the steps, and then substituting for L, w, and A, to finish, then you may need no further help on this.