Question 1058783
The old press takes x hours alone or 1/x of the job per hour.
The new press takes x-3 hours alone or 1/(x-3) of the job per hour.
(5/x)+(3/x)+(3/x-3)=1, because the second and third terms are both punches
Multiply everything by x(x-3) to clear fractions
5(x-3)+3(x-3)+3x=x^2-3x
5x-15+3x-9+3x=x^2-3x
x^2-14x+24=0
(x-12)(x-2)=0
x=12 or 2 hours
3 can't work or the second press would take -1 hours
They are 12 hours and 9 hours respectively
(5/12)+(3/12)+(3/9) represents 8 hours by the first press and 3 hours for the second.  That equals 1.