Question 701837
If the multiple is {{{n}}} then the three consecutive numbers would be:
{{{ 7n }}}, {{{7n+7}}} and {{{ 7n+14 }}}


And so:
{{{ (7n) + (7n+7) + (7n+14) = 777 }}}
{{{ 21n + 21 = 777 }}}
{{{ 21n = 756 }}}
{{{ n = 36 }}}


So the three numbers are:
252, 259 and 266