Question 270949
Let {{{1.5a}}} = cost of the 1st lesson
Then {{{a}}} = cost of each of the next 7 lessons
{{{1.5a + 7a = 153}}}
{{{8.5a = 153}}}
{{{a = 18}}}
The 1st lesson cost 
{{{1.5a = 1.5*18}}}
{{{1.5a = 27}}}
The 1st lesson cost $27
check:
{{{1.5a + 7a = 153}}}
{{{1.5*18 + 7*18 = 153}}}
{{{27 + 126 = 153}}}
{{{153 = 153}}}
OK