Question 1013990
How you mean the rate is uncertain.  The assumption made will be r is the one-man rate and that twice
the number of men would be used to make the group rate double.


The first part gives {{{18r*35=6}}}
{{{r=6/(18*35)}}}
{{{r=6/(3*6*35)}}}
{{{r=1/(3*35)}}}------the one-man rate.


Using 2 men would give  {{{2r=2/(3*35)}}} as the TWO-man rate.
Question would be how many of two-men build 4 ships in 14 days?
n, how many of two-men,
{{{highlight_green(n*(2/(3*35))*14=4)}}}


{{{n=4(3*35)/(2*14)}}}
{{{n=(4*3*5*7)/(2*2*7)}}}
{{{n=15}}}


This should be {{{2*15=highlight(30*men)}}}.



The other interpretation from the beginning may be  EACH man will work at DOUBLE his typical rate
so the one-man rate could be  {{{2/(3*35)}}}, and then {{{n=15}}} would really be FIFTEEN men.