Question 358985
So far they their winning ratio is {{{10/15}}}. After x more games, their winning ratio would be {{{(10+x)/(15+x)}}}, and this should be 0.75.  Hence
{{{(10+x)/(15+x)=0.75}}}.
{{{10+x = 11.25+0.75x}}},
{{{0.25x = 1.25}}}, and
{{{x = 5}}}.
Thus they play 5 more games.