Question 497884
{{{100}}} join both teams
That means {{{ 175 - 100 = 75 }}} want to join 
only the tennis team
And {{{ 320 - 100 = 220 }}} want to join
only the math team.
The number joining teams is {{{ 75 + 100 + 220 = 395 }}}
The number joining neither is {{{ 700 - 395 = 305 }}}