Question 287829
The 2nd day would be 
{{{7+2}}} blocks
then
{{{7 + 4}}}
{{{7 + 6}}}
{{{7 + 8}}}
The formula for this is:
{{{7 + 2*(d-1)}}} where {{{d}}} is the day number
given:
{{{7 + 2*(d-1) = 25}}}
{{{7 + 2d - 2 = 25}}}
{{{2d = 25 + 2 - 7}}}
{{{2d = 20}}}
{{{d = 10}}}
she was in training 10 days
check:
{{{7 + 2*(10 - 1) = 25}}}
{{{7 + 18 = 25}}}
{{{25 = 25}}}
OK