# Thread: Help with this straight forward question

1. ## Help with this straight forward question

Need to put this in report but differnet pple got differnet ways to calculate this.

Machine A finish the job in 1 second

Machine B finish the job in 5 seconds

Conclusion :
Machine A is ___% faster than Machine B

What is your answer? remeber the key word is "faster than".

What about this?
Machine A is ___% as fast as Machine B

think until headache liao

2. ## Re: Help with this straight forward question

80% faster

A =1 second
b = 5 seconds

so 4 seconds faster

4 seconds out of 5 seconds = 80%

3. ## Re: Help with this straight forward question

hmm...why is it not 4 sec out of 1 sec = 400%??

since Machine A is the main subject

Machine A is 4 times faster than Machine B right?

4 times = 400%

4. ## Re: Help with this straight forward question

How about:
Machine A is 4 times faster than Machine B,
as Machine A can process 4 times more than the same amount of time while Machine B doing the same process.

Does it mean that Machine A is 400% faster than Machine B???

opps I am late...

5. ## Re: Help with this straight forward question

In the time that machine B completes its task. Machine A would have done it 5 times.. so its 5x (500%) faster.

6. ## Re: Help with this straight forward question

My answer is 400%

7. ## Re: Help with this straight forward question

Originally Posted by Wai
Need to put this in report but differnet pple got differnet ways to calculate this.

Machine A finish the job in 1 second

Machine B finish the job in 5 seconds

Conclusion :
Machine A is ___% faster than Machine B

What is your answer? remeber the key word is "faster than".

What about this?
Machine A is ___% as fast as Machine B

think until headache liao
Machine A is 4 secs faster than Machine B.
Machine A is 1/5 times as fast as Machine B.

Convert to %
Machine A is 4/5 x 100% = 80% faster than Machine B.
Machine A is 1/5 x 100% = 20% as fast as Machine B.

Hope I got it right... I stand corrected of course....
Damn the bloody English Language...

Just another 1/2 f-stop please...

8. ## Re: Help with this straight forward question

Ok,
just my personal understanding, so take with a pinch of salt.

If machine A took 1 sec and machine B took 1 sec, then A is 100% AS FAST as B but 0% FASTER than B.

Since machine A took 1 sec and machine B took 5 seconds, then machine A is 4 sec faster than B and is therefore 400% FASTER than B.

The second question is not answerable without breaking the rules as english grammer, but if I were to guess, I'd say machine A is 500% AS FAST as machine B.

9. ## Re: Help with this straight forward question

i guess the majority is with 400% here..
I'm also with 400%.. why not just start a poll?

10. ## Re: Help with this straight forward question

Originally Posted by Zplus
Machine A is 4 secs faster than Machine B.
Machine A is 1/5 times as fast as Machine B.

Convert to %
Machine A is 4/5 x 100% = 80% faster than Machine B.
Machine A is 1/5 x 100% = 20% as fast as Machine B.

Hope I got it right... I stand corrected of course....
Damn the bloody English Language...

Just another 1/2 f-stop please...
Gee... I just spotted my own mistake....
Machine A is 5 times as fast as Machine B.

Hence,
Machine A is 5 x 100% = 500% as fast as Machine B.

11. ## Re: Help with this straight forward question

Machine A is 400% faster than Machine B

Machine A is 500% as fast as Machine B

"0% faster than" represents same speed (i.e.: as fast as).
"100% faster than" represents twice as fast.
therefore, "400% faster than" represents 5 times as fast.

.

12. ## Re: Help with this straight forward question

Originally Posted by AReality
Machine A is 400% faster than Machine B

Machine A is 500% as fast as Machine B

"0% faster than" represents same speed (i.e.: as fast as).
"100% faster than" represents twice as fast.
therefore, "400% faster than" represents 5 times as fast.

.
i agreed with this.

13. ## Re: Help with this straight forward question

thanks everyone, will follow the majorities' answer and use 400% faster

14. ## real maths

let speed of A be "a" jobs per unit time
let speed of B be "b" jobs per unit time

suppose A and B both start to do x number of jobs

from given data,
for A: a = number of jobs done/time taken = x/1 = x -----(1)
for B: b = number of jobs done/time taken = x/5 -----(2)

substitute (1) into (2) : hence b = x/5 = a/5
i.e. a = 5b ------(3)

thus speed difference = a-b = 5b-b =4b [using equation (3) ]
percentage difference = (4b/b) x 100% =400%

hence Machine A is 400% faster than Machine B

comparing speed again, a/b = 5b/b = 5 [using equation (3) ]
expressed as percentage: (a/b) x 100% = 5x100% =500%

hence Machine A is 500% as fast as Machine B

[Q.E.D]

PS: the main idea here is to try to obtain equation (3), which states that a=5b i.e. it directly tells you that machine A is 5 times as fast as machine B. with equation (3), all other related questions can be solved

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