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# GCSE Maths Help and Chat Thread watch

1. (Original post by NothingButWaleed)
What does tagging do?
2. (Original post by notnek)
oh ok
3. (Original post by NothingButWaleed)
If half the machines are used it would take double the time to make all the bottles, hence, 4 machines would take 10 days!
That's right. But you are told that the 4 machines worked for 2 days so they can't have made all the bottles. How much of the bottles did they make?
4. (Original post by NothingButWaleed)
If half the machines are used it would take double the time to make all the bottles, hence, 4 machines would take 10 days!
That would be the case if only 4 machines were in operation for the entirety of the time that it takes for the bottles to be manufactured.

However,

From the 3rd day, all 8 machines are used to make the bottles.
How can you use your deduction that 8 machines take half as long as 4 machines to create the same amount of bottles?
5. (Original post by notnek)
That's right. But you are told that the 4 machines worked for 2 days so they can't have made all the bottles. How much of the bottles did they make?
i dont know
6. (Original post by _gcx)
That would be the case if only 4 machines were in operation for the entirety of the time that it takes for the bottles to be manufactured.

However,

How can you use your deduction that 8 machines take half as long as 4 machines to create the same amount of bottles?
What does "deduction" mean?
7. (Original post by NothingButWaleed)
i dont know
Ignore what I said. _gcx will help you solve the question in a better way.
8. (Original post by notnek)
Ignore what I said. _gcx will help you solve the question in a better way.
But i dont understand what he is talking about!
9. (Original post by _gcx)
That would be the case if only 4 machines were in operation for the entirety of the time that it takes for the bottles to be manufactured.

However,

How can you use your deduction that 8 machines take half as long as 4 machines to create the same amount of bottles?
Maybe multiply it by 2?
10. (Original post by NothingButWaleed)
i dont know
We know that 1 day with 8 machines will produce the same amount of bottles as 2 days with 4 machines. How can we use this information to work out how long it takes running with 4 machines for 2 days, then 8 machines after that?
11. (Original post by NothingButWaleed)
But i dont understand what he is talking about!
This is a tough question that most found hard - you just need a bit more explanantion and I think you'll get it, you just need to be patient! I can help later if _gcx isn't free.
12. (Original post by _gcx)
We know that 1 day with 8 machines will produce the same amount of bottles as 2 days with 4 machines. How can we use this information to work out how long it takes running with 4 machines for 2 days, then 8 machines after that?
I would use ratios...

1 day :8 machines = same amount of bottles
2 days:4 machines = same amount of bottles

So..
4 days:2 machines = same amount of bottles
?????
13. (Original post by NothingButWaleed)
I would use ratios...

1 day :8 machines = same amount of bottles
2 days:4 machines = same amount of bottles

So..
4 days:2 machines = same amount of bottles
?????
This might be a better way to think about it: Think of the 5 days as a countdown.

Every day at half efficiency (4 machines) subtracts half (for essentially a half day's work).

Every day at full efficiency (8 machines) subtracts one (for a full day's work)
14. (Original post by _gcx)
this might be a better way to think about it: Think of the 5 days as a countdown.

Every day at half efficiency (4 machines) subtracts half (for essentially a half day's work).

Every day at full efficiency (8 machines) subtracts one (for a full day's work)
whaaatttt???
15. (Original post by NothingButWaleed)
I would use ratios...

1 day :8 machines = same amount of bottles
2 days:4 machines = same amount of bottles

So..
4 days:2 machines = same amount of bottles
?????
Do you agree that 4 machines in 2 days make the same amount of bottles as 8 machines in 1 day?

So if you like we can replace "4 machines in 2 days" to "8 machines in 1 day" in the question. So the question becomes:

The 8 machines in the factory could make all the bottles in 5 days.
All the machines work at the same rate.

Stage 1 : For 1 day, 8 machines are used to make the bottles.
Stage 2: All 8 machines are used to make the bottles.

How long wil stage 2 take?
16. (Original post by notnek)
Do you agree that 4 machines in 2 days make the same amount of bottles as 8 machines in 1 day?

So if you like we can replace "4 machines in 2 days" to "8 machines in 1 day" in the question. So the question becomes:

The 8 machines in the factory could make all the bottles in 5 days.
All the machines work at the same rate.

Stage 1 : For 1 day, 8 machines are used to make the bottles.
Stage 2: All 8 machines are used to make the bottles.

How long wil stage 2 take?
5 days
17. (Original post by notnek)
Do you agree that 4 machines in 2 days make the same amount of bottles as 8 machines in 1 day?

So if you like we can replace "4 machines in 2 days" to "8 machines in 1 day" in the question. So the question becomes:

The 8 machines in the factory could make all the bottles in 5 days.
All the machines work at the same rate.

Stage 1 : For 1 day, 8 machines are used to make the bottles.
Stage 2: All 8 machines are used to make the bottles.

How long wil stage 2 take?
OHHHHHHHHHHH.....
so 1 day for 8 bottles and 5 days for the rest so 1+5 = 6 days in total!
This is such a good way to understand it the other ways were so confusing
18. (Original post by NothingButWaleed)
5 days
No, notice that stage 1 took 1 day and 8 machines make all the bottles in 5 days. So how many extra days are needed for stage 2?
19. (Original post by NothingButWaleed)
OHHHHHHHHHHH.....
so 1 day for 8 bottles and 5 days for the rest so 1+5 = 6 days in total!
This is such a good way to understand it the other ways were so confusing
No this isn't right but you're close. Read my post above.

Also remember that "1 day for 8 bottles" is used as a technique to find the number of days in stage 2. But stage 1 actually took 2 days if you read the question.
20. (Original post by notnek)
No, notice that stage 1 took 1 day and 8 machines make all the bottles in 5 days. So how many extra days are needed for stage 2?
idk how can i work that out?

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