Question 1068277
Rate x Time = Output
Let say that eating a gallon of ice cream requires an output (or input) of 100 units (it's an arbitrary number, it could have been 1 or 27 or any other non-zero number).
{{{J}}}-Jenny's rate
{{{P}}}-Penny's rate
{{{L}}}-Lenny's rate
So,
{{{(J+P)(2)=100}}}
1.{{{J+P=50}}}
and
{{{(P+L)(1+2/3)=100}}}
{{{(P+L)(5/3)=100}}}
2.{{{P+L=60}}}
and
{{{(J+P+L)(1)=100}}}
3.{{{J+P+L=100}}}
Subtracting 1 from 3,
{{{J+P+L-J-P=100-50}}}
{{{L=50}}}
So,
{{{P+50=60}}}
{{{P=10}}}
and
{{{J+10+50=100}}}
{{{J+60=100}}}
{{{J=40}}}