Question
A new photocopier can make 72 copies in 2 min. When an older photocopier is working, the two photocopiers can make 72 copies in 1.5 min. How long will it take the older photocopier working alone to make 70 copies?
Answers
Katie
How would you set it up? Would it be (72/2) + (72/1.5)= (70/x)? we didn't do examples in class
Damon
new --> 36 copies/min
old --> n copies/min
new + old = (n+36) copies/min
(n+36)copies/min * 1.5 min = 72 copies
1.5 n + 54 = 72
1.5 n = 18
n = 12 copies/min
12 copies/min * t = 70 copies
t = 35/6 = 5.83 min
old --> n copies/min
new + old = (n+36) copies/min
(n+36)copies/min * 1.5 min = 72 copies
1.5 n + 54 = 72
1.5 n = 18
n = 12 copies/min
12 copies/min * t = 70 copies
t = 35/6 = 5.83 min
Damon
I wrote out all those copies/ min and such for a reason. In problems like this if you keep track of the units, it is hard to go far off course.
8===D
I am stuck on this one too :(