Question 1101124
{{{13*(2/3)}}}


Simple Proportion is the most you need.

Rate is  {{{15/13}}}{{{widgets/hours}}}.


How Many in 10 hours?
{{{15/13=10/x}}}


{{{x/10=13/15}}}


{{{x=10(13/15)}}}


{{{x=(2*13)/3}}}