CAT #3- IR Zinc Lead Deposits Wrong Explanation/ Answer

[Adadelrosso]

The first question statement states "For the two countries with the greatest total ore tonnage, zinc deposits in tons are more than 1.5 times lead deposits in tons.".

The explanation states: "For Australia, lead deposits make up 4.39 percent. Multiply 4.39 × 1.5 = 6.59, which is less than the actual zinc grade percentage of 6.97 in Australia. In this case, too, zinc deposits are more than 1.5 times lead deposits."

Isn't 6.59 greater than 6.97? Please advise.

[RonPurewal]

Isn't 6.59 greater than 6.97? Please advise.

hmm? no, 6.59 is definitely less than 6.97.

take a look at those numbers again - maybe you're only looking at the last digit, or something?

[imhimanshujaggi]

Hello MGMAT Instructors,
The question asks us to find out if zinc deposits in tons are more than 1.5 times lead deposits in tons.

Values Given are:

Total Ore Tonnage Zinc Grade(%) Lead Grade(%)
1939.5(Aust) 6.97% 4.39%
2644.8(US) 3.88 2.38

While solving this question during exam time, I calculated the difference between Zinc grade% and Lead Grade %. However, after looking at the explanation, I found that the question requires us to find (Lead Grade% * 1.5)

My doubt is what would be the wording of the question in case we need to perform the following operation:
LeadGrade% + 1.5 = Zinc Grade%.


Regards
H

[tim]

It looks like that equation would be for a situation where the percentage of zinc would be 1.5% more than the percentage of lead.

[morr.lasten]

I am come a cross to your site and found it according to my need and demand.

[tim]

Your "demand"? Okay, good to know I guess.. :)

[RonPurewal]

Hello MGMAT Instructors,
The question asks us to find out if zinc deposits in tons are more than 1.5 times lead deposits in tons.

Values Given are:

Total Ore Tonnage Zinc Grade(%) Lead Grade(%)
1939.5(Aust) 6.97% 4.39%
2644.8(US) 3.88 2.38

While solving this question during exam time, I calculated the difference between Zinc grade% and Lead Grade %. However, after looking at the explanation, I found that the question requires us to find (Lead Grade% * 1.5)

My doubt is what would be the wording of the question in case we need to perform the following operation:
LeadGrade% + 1.5 = Zinc Grade%.


Regards
H

Actually, the wording in that case would have to use "percentage points", NOT percent.

A "percentage point" represents the actual difference between the percentages. You have to be very careful with "percent" vs. "percentage point" in terms of increases and decreases, because "percent increase" is already defined -- as something that's not the same as percentage points.

E.g.,

* 50% of something is 10 percentage points higher than 40% of something.
(50 - 40 = 10)

* However, 50% of something is 25 percent higher than 40% of the same thing. (Standard calculation of percent change: ((50 - 40)/40)

So, in your question, you'd need "1.5 percentage points higher than..."

I'm not sure whether GMAC tests "percentage points". However, GMAC can certainly test the fact that, say, 8% is NOT "1.5% greater than" 6.5%.

[tim]

Good point about the distinction between percentage and percentage points. Thanks, Ron!