Typical %% test

Total
#1

Total Energy Usage
1990: 17 000
2000: 15 000
2010: X (today)

If the total energy usage today has reduced by 6% compared to that of 2000,by how much has today’s usage reduced when compared to 1990?

A)82.9% B)20.1% C)17.8% D)Cannot say

Please show all steps of calculation.

#2

Total energy use today reduced by 6% of 2000 usage.

So 94% of 2000 value = 0.94 * 15000 = 14100
Compared with 1990, 2010 usage reduced by (17000 - 14100) = 2900
Therefore, expressed as a percentage this is a reduction = 2900/17000 * 100% = 17.058%

So it should be C…

#3

15000 x 0.94 = 14100.

14100/17000 = 0.829, 82.9% - That is, todays usage is 82.9% of what it was in 1990.

Or am I wrong?

#4

any other inputs??

#5

Reg,

your calculation is correct, but that is not what is asked in the question. The question is how much has today’s usage declined in comparison with 1990. If today’s usage is 82.9% of what it was in 1990 and 1990 was 100%: 100% - 82.9% = 17.1% (approximately)

That’s how I understand it. I would agree with the09

#6

Uybert,

You’re right - but when I calculated it, the answer was closer to 17.1% than 17.8%(The option given), so I assumed it was a wording error in the question. It’s a poor question in my opinion!

#7

Apparently it’s 20.1%.

15000 in 2000.

Given that it is 6% lower 2010 vs. 2000;

15000/1.06 = 14159.06.

Then compare it against 1990 as follows;

17000/14159.06 = 20.1%

Therefore answer is B.

I did this question for a practice on assessmentday website and I got the same answer as everyone else above. Though I don’t really get their solution to be honest. I personally feel the question is misleading. I don’t know the rules here for linking, but for the actual question it’s their 2nd numerical question 5. Any thoughts or enlightenments?

#8

finalist is right

since 2000 it has reduced by 6% and today’s usage is X then

X*(1+0.06) = 15000

So

X=15000/1.06

Now, I c, why most of the bright students fail the tests! just pay attention to details and read until you understand what they mean.
good luck

#9

If something has reduced by 6% since 2000, then the 2010 value is 94% of the 2000 one.

Therefore, the calculation is 0.94 * 15000.

The calculation [15000/1.06] would be appropriate if the 2010 value was 15000, and had increased by 6% since 2000, and you had been asked to find out what the 2000 value was.

#10

I still think the answer is 17.1%. I’ve found a different version of this test http://www.assessmentday.co.uk/Numerical%20Reasoning%20Test%201.pdf with 17.1% instead of 20.1% among the answers (Q5). So there’s probably just an error in the question.
you can find the correct answers at the end of the pdf document