Question 983047
1st session:
{{{ 10 }}} lengths
2nd session:
{{{ 10 + 2 }}}
3rd session:
{{{ 10 + 4 }}}
4th session:
{{{ 10 + 6 }}}
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Let {{{ n }}} = the number of the session
The lengths Ann swims at session {{{ n }}} is:
{{{ 10 + 2*( n-1 ) = 50 }}}
{{{ 10 + 2n - 2 = 50 }}}
{{{ 2n = 42 }}}
{{{ n = 21 }}}
After 21 sessions, Ann swims 50 lengths
for the 1st time