Question 1006967: This problem is really confusing me. I've been trying for a while but just don't know how to do it. Could you help?
A factory has an order for 23,500 paper clips. Machine A can make 1500 paper clips per hour while Machine B can make 2500 paper clips per hour. Machine A starts at 8:00 A.M. and Machine B starts at 1:00 P.M. At what time will the two machines complete the job?
Found 3 solutions by ptaylor, fractalier, josmiceli:
Answer by ptaylor(2198)   (Show Source):
You can put this solution on YOUR website! OK, let t=time that both machines finish the job
Now we know that machine A and B working together makes 1500+2500=4000 clips per hour
Now machine A works alone for 5 hours(8am-1pm) before machine B starts, so Machine A makes 1500*5=7500 clips leaving 23,500-7500=16,000 clips yet to be made.
Working together, machine A and machine B can make 16,000 clips in 16,000/4000=4 hours:
Sooo t=1:00pm +4 hours=5:00pm
Hope this helps---ptaylor
Answer by fractalier(6550)  (Show Source):
You can put this solution on YOUR website! Imagine machine A working from 8 am until 1 pm.
In those five hours, it produces 5(1500) = 7500 paper clips.
That means there are 23,500 - 7,500 = 16,000 paper clips to go.
When both machines run, they produce 1500+2500 = 4,000 paper clips an hour.
Since they have to make 16,000 more paper clips, they work together for 16,000/4,000 = 4 more hours.
They will be done at 5 pm.
Answer by josmiceli(19441)  (Show Source):
|
|
|
