application problem

Question

2 printers can print 4 reams of aper in 30 minutes. If you had 3 printers and 5 reams to print, how many minutes would it take? I have to write an equation.

Answer 1

If 2 printers can print 4 reams in 30 minutes, it would take 1 printer twice as long.  Therefore 1 printer can print 4 reams in 60 minutes (1 hour).  Another way to say this is a printer works at a rate of 4 reams/hr.  If you have three printers, they should be able to print 3 times as many in an hour, hence 12 reams / hour.

 

You can therefore solve the following proportion:

 

12 rms    =   5 rms     this can be simplified to:

60 min         x min    

 

1 ream    = 5 rms      multiply top and bottom of left by 5 gives  x = 25 minutes

5 min        x min