#### Answer

approximately 65 minutes

#### Work Step by Step

$3*2=6$
$2*3=6$
Jeff finished 3 tables in 6 minutes, and Tiffany finished 2 tables in 6 minutes. Combined, they finished 5 tables in 6 minutes. Thus, they can finish 45 tables in 54 minutes.
Stacie finishes one table in 3 minutes. Thus, Stacie finished 18 tables in 54 minutes. Nick finishes one table in 3.5 minutes. Thus, Nick finished 15.4 tables in 54 minutes. 33.4 total tables are done.
$(x/3+x/4+x/5+x/3.5) = 11.6$
$210*(x/3+x/4+x/5+x/3.5) = 11.6*210$
$70x+52.5x+42x+60x = 2436$
$224.5x=2436$
$x=2436/224.5$
$x=10.85$
$10.85+54 = 64.85$