Question

A new photocopier can make 72 copies in 2 min. When an older photocopier is operational, the two photocopiers together can make 72 copies in 1.5 min. How long would it take the older photocopier to make 72 copies working alone?

Answer 1

@hartnn @amistre64 @ganeshie8 @dumbcow

Answer 2

solve this by adding rates

new copier has a rate of 72/2 or 36 copies per minute
old copier has unknown rate "x"

combined rate is 72/1.5 or 48 copies per minute

--> 36 + x = 48
--> x = 12

So old copier has rate of 12 copies per minute
--> 12*time = 72
--> time = 72/12 = 6

It takes old copier 6 minutes to make 72 copies

Answer 3

@dumbcow yay thank u so much you saved my life!

Answer 4

yw :)

Answer 5

Another approach.\[\frac{72}{x}+\frac{72}{2}=\frac{72}{\frac{15}{10}} \]
x = 6

Answer 6

@robtobey okay thank you! :)

Answer 7

Your welcome.