Question 344371
Assume there are 4 weeks per month.
Then the cost per week would be 
{{{W=115/4}}}
.
.
.
For a more exact value, since there are 12 months per year you would spend {{{Y}}} per year.
{{{Y=12(115)}}}
Since there are 52 weeks in a year, then the cost per week would be,
{{{W=Y/52=(12(115))/52}}}
.
.
.
Work those values out for whichever scenario fits best.