Question 890810
x and y rates for hot pipe and cold pipe.
2x=3y and x+y=1300.
That translation from words into symbols is really all you need.  Two linear equations in two unknowns.


Elimination:
2x+2y=2600 and 2x-3y=0;
2x+2y-(2x-3y)=2600-0
5y=2600
y=26*100/5
y=20*26
y=520 and x=1300-520