Question 323592
In words:
(printing rate of old printer) + (printing rate of new printer) = (printing rate together)
And, making this more detailed:
(o.p. rate in checks/min) + (n.p. rate in checks/min) = (rate together in checks/min)
Let old printer's rate = {{{r}}} checks/min
given:
New printer's rate = {{{3r}}} checks/min
Printing rate together = {{{1/6}}} one check printing job/min
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Note that I am calling all the checks printed = 1 printing job
{{{3r + r = 1/6}}}
{{{4r = 1/6}}}
{{{r = 1/24}}}
So, the old printer's rate is 1 check printing job in 24 min
{{{3r = 3/24}}}
{{{3r = 1/8}}}
So, the new printer's rate is 1 check printing job in 8 min
check answer:
{{{3/24 + 1/24 = 1/6}}}
{{{4/24 = 4/24}}}
OK