Question 339785
Let H be the number of Helen's stamps, L the number of Lionel's stamps,
{{{H=L+5}}}
{{{H+L=45}}}
Substitute,
{{{L+5+L=45}}}
{{{2L=40}}}
{{{L=20}}}
{{{H=20+5=25}}}
Helen has 25 stamps, Lionel has 20 stamps.