Question 403988
Let {{{n}}} = lesson number starting with {{{n=1}}} on 1st week
{{{240 - .15*240*n}}} = how much she has left after {{{n}}} weeks
Make this equal to zero which means she has used up all of savings
{{{240 - .15*240*n = 0}}}
{{{36n = 240}}}
{{{n = 6.667}}}
She can afford 6 lessons