The advanced technology of ski boots and bindings has brought a dramat

You can look at the argument in math terms.

1950: 9 injuries on the slopes per 1000 skiers --> Off slopes injuries are 10% of injuries. So, 9 on slopes injuries per 1000 must be 90% of injuries.

Total injuries per 1000 1950: 9 on slopes + 1 off slopes = 10 total

1980: 3 injuries on the slopes per 1000 skiers --> Off slopes injuries are 25% of injuries. So, 3 on slopes injuries per 1000 must be 75% of injuries.

Total injures per 1000 1980: 3 on slopes + 1 off slopes = 4 total

Now let's look at the answer choices.

(A) As the number of ski injuries that occur on the
slopes decreases, the number of injuries that
occur on the premises of ski resorts increases.

No. The off slope number per 1000 did not change.

(B) The amount of alcohol consumed per skier
increased between 1950 and 1980.

There is no reason to believe this, especially as off slope injuries did not increase.

(C) The technology of ski boots and bindings
affects the incidence of each type of
ski-related injury.

Actually, off slope injuries did not change even after the introduction of the ski boots and bindings.

(D) If the technology of ski boots and bindings
continues to advance, the incidence of
ski-related injuries will continue to decline.

This seems likely, but the prompt does not actually indicate that this is the case. The prompt discusses what happened in the past without saying much that indicates what would happen in the future should the technology continue to advance.

(E) Injuries that occurred on the slopes of ski
resorts made up a smaller percentage of
ski-related injuries in 1980 than in 1950.

This is true. In 1950, on slopes injuries constituted 90% of injuries. In 1980, on slopes injuries constituted 75% of injuries.

The correct answer is E.
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The number of injuries on the slopes has decreased in 1980 compared to 1950.But the total number of injuries has increased .Hence the percentage of injuries on the slope has decreased in 1980 compared to 1950.Hence answer is E.
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We’re told that, from 1950 to 1980, the percentage of all ski-related injuries at ski resorts that did not occur on the slopes increased from 10% to 25%. That must mean that the percentage of ski-related injuries at ski resorts that did occur on the slopes must have decreased over that same period. Think about it this way: there are only two possible alternatives for a ski related injury: either it occurs on the slopes or it does not occur on the slopes. So if the share of ski-related injuries represented by one type of injury goes up, the share represented by the other type MUST go down. That’s choice (E).

(A) We have no information about the number of the different types of ski-related injuries occurring, only about the percentage of total injuries represented by the two different types of injuries. Since we don’t know how or whether the total number of injuries changed, we can’t infer (A).

(B) We can infer nothing about the amount of alcohol consumed. It’s true that increased alcohol consumption causes an increase in injuries off the slopes, but we don’t know that those injuries have increased numerically, nor do we know that alcohol consumption is the only thing that could bring about an increase.

(C) Although the stimulus says improved ski boots and bindings have decreased the incidence of injuries on the slopes, it never implies that they have any effect on off-slope
injuries.

(D) is unwarranted for two reasons: first, the fact that better boots and bindings have reduced the incidence of on-slope injuries in the past is no guarantee that they will do so in the future and, second, (D) speaks of “ski-related injuries” in general, and we have no reason to believe that boots and bindings have any effect on the incidence of off-slope injuries.

(A) As the number of ski injuries that occur on the slopes decreases, the number of injuries that occur on the premises of ski resorts increases. - Relation between ski injuries on slopes and premises of ski resorts is not mentioned in the argument - Incorrect
(B) The amount of alcohol consumed per skier increased between 1950 and 1980. - Cannot be inferred from the passage - Incorrect
(C) The technology of ski boots and bindings affects the incidence of each type of ski-related injury. - Out of scope - Incorrect
(D) If the technology of ski boots and bindings continues to advance, the incidence of ski-related injuries will continue to decline. - Cannot be inferred with the information given in the passage - Incorrect
(E) Injuries that occurred on the slopes of ski resorts made up a smaller percentage of ski-related injuries in 1980 than in 1950. - The injuries on the slopes has decreased from the year 1950 to 1980. That would automatically decrease the percentage share of injuries on slopes over the total number of injuries - Correct

I used some Mathematics to tackle this question...

1.) 9 Injuries on the slopes in 1950, 10% of all injuries were not on the slopes. So we can say that 1 injury occurred in the premises of the ski resort.

1/10- 10% of all Injuries are on the premises.

2.) 3 Injuries on the slopes in 1980, 25% of all injuries were not on the slopes. So we can say that 1 injury occurred in the premises of the ski resort.

1/4- 25% of all Injuries are on the premises.

(A) As the number of ski injuries that occur on the slopes decreases, the number of injuries that occur on the premises of ski resorts increases.---- Incorrect, as you can see above that number of ski injuries decreases from 9 to 3 but then number of injuries that occur on the premises stay the same.
(B) The amount of alcohol consumed per skier increased between 1950 and 1980.--- Out of scope. No information regarding alcohol consumption
(C) The technology of ski boots and bindings affects the incidence of each type of ski-related injury.---- Each type is taking it too far isn't it??? The technology must have affected some of the injuries but definitely not all...
(D) If the technology of ski boots and bindings continues to advance, the incidence of ski-related injuries will continue to decline.---- This is a future event. What if there cannot be any more decline in the injuries no matter what you do with ski boots and bindings...
(E) Injuries that occurred on the slopes of ski resorts made up a smaller percentage of ski-related injuries in 1980 than in 1950.--- CORRECT, as you can see in the analysis above, Injuries that occurred on the slopes in 1980-3/4=75% whereas in 1950- 9/10-90%. Absolutely TRUE.

B. We're not told that the amount of alco comsumed per skier has been increased. So it could have been remained the same.
C. Tricky one, however it covers all types of ski-related injuries and since we are told that off-slope injuries are classified as ski-related injuries as well that statement cannot be inferred from the argument as long as despite the fact the ski&bindings technology advances we see that it doesn't affect positively off-slope injuries.

A) Is not inferrable. A decrease in the % of slope injuries will necessarily lead to an increase of % non-slope injuries in terms of the % of all ski injuries. So we do not have to have more injuries on the non-slope side. It could stay the same or even drop, just not by as much as the slope side.

B) Could be true, not necessarily true. This can be thought of as reversed logic. We know that alcohol could lead to the increase. And we do have an increase. Does not mean alcohol was the cause.

C) Each type of ski injury? We know it is affecting ski injuries, but not every type.

D) Temporal flaw. We cannot infer anything about the future.

E) Wins by default. However, it can still be proved.

We know that the % of slope injuries in 1950 was 90% while in 1980 it was 75%.
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Saw the question rated as "hard"-LSAT question, was anxious to press the E) button for a whole lot of time but it turns out to be that straight forward - I am so prone to looking for traps that I went through the numbers 10 times - lol

good one!
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Took me way too long...

The advanced technology of ski boots and bindings has brought a dramatic drop in the incidence of injuries that occur on the slopes of ski resorts: from 9 injuries per 1,000 skiers in 1950 to 3 in 1980. As a result, the remainder of ski-related injuries, which includes all injuries occurring on the premises of a ski resort but not on the slopes, rose from 10 percent of all ski-related injuries in 1950 to 25 percent in 1980. The incidence of these injuries, including accidents such as falling down steps, increases with the amount of alcohol consumed per skier.

Which one of the following can be properly inferred from the passage?


(A) As the number of ski injuries that occur on the slopes decreases, the number of injuries that occur on the premises of ski resorts increases. X
No...this is taking things way too far.

(B) The amount of alcohol consumed per skier increased between 1950 and 1980. X
Yes the incidence of ski-related injuries goes up as the amount of alcohol consumed per skier increases, but this is not the same as saying the amount of alcohol consumed per skier did in fact increase ...it may have, it may have not.

(C) The technology of ski boots and bindings affects the incidence of each type of ski-related injury. X

There's not enough info. to infer this.

(D) If the technology of ski boots and bindings continues to advance, the incidence of ski-related injuries will continue to decline.

Past is not indicative of the future. This choice also fails to take into account other reasons for injuries (e.g. horseplay)

(E) Injuries that occurred on the slopes of ski resorts made up a smaller percentage of ski-related injuries in 1980 than in 1950. CORRECT
Injuries that occurred on the resort increased from 10-25% ...so such injuries take a bigger chunk out of the pie...as a result the percentage of injuries that occurred because of the slope decreased (stated in the passage).
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I narrowed it down to B & E, and had a problem eliminating B. So, just delineating how I went about it.

Let's look at option B.

Mathematically:

In 1950:

Number of Skiers = 1000
Number of on-slope injuries = 9 (given 9 injuries per 1000 skiers)
Number of non-slope injuries = 1 (because non-slope injuries were 10% of all injuries. So, 90% of all injuries = 9)

Let's say consuming >= 100 mL alcohol makes one prone to non-slope injuries.
So, alcohol consumption rate = 1*100mL/1000 skiers

In 1980:

Number of Skiers = 1000
Number of on-slope injuries = 3
Number of non-slope injuries = 1 (because non-slope = 25% of all injuries.)

So, alcohol consumption rate = 1*100mL/1000

So, it is possible that the alcohol consumption rate didn't increase at all.

Also, we can argue that since the number of non-slope injuries in 1980 < in 1950, the alcohol consumed in 1980 < alcohol consumed in 1950. So, the rate in 1980 can at best be equal to the rate in 1950.

Option E is justified.

In 1950:

Contribution of non-slope injuries = 10%
Therefore, Contribution of slope-injuries = 90%

In 1980:

Contribution of non-slope injuries = 25%
Therefore, Contribution of slope-injuries = 75%

Comparing [Percentage of on-slope injuries] in 1950 to [Percentage of on-slope injuries] in 1980 = 90% vs 75%. E is correct.

Hello Marty,
The question stem "from 9 injuries per 1,000 skiers in 1950 to 3 in 1980." doesn't explicitly mention that 3 were injured out of 1000 skiers in 1980. What if the number of skiers also declined, leading to fewer injuries in 1980? That's why I crossed E and chose B.

The advanced technology of ski boots and bindings has brought a dramatic drop in the incidence of injuries that occur on the slopes of ski resorts: from 9 injuries per 1,000 skiers in 1950 to 3 in 1980. As a result, the remainder of ski-related injuries, which includes all injuries occurring on the premises of a ski resort but not on the slopes, rose from 10 percent of all ski-related injuries in 1950 to 25 percent in 1980. The incidence of these injuries, including accidents such as falling down steps, increases with the amount of alcohol consumed per skier.

Which one of the following can be properly inferred from the passage?

(A) As the number of ski injuries that occur on the slopes decreases, the number of injuries that occur on the premises of ski resorts increases. - WRONG. It suggests that there's some correlation between the two types of injuries but it is not inferable from the passage. In that percentage terms are used wherein here it is numbers.

(B) The amount of alcohol consumed per skier increased between 1950 and 1980. - WRONG. Not at all inferable as alcohol amount was per skier but this option says in terms of total amount which is not inferable.

(C) The technology of ski boots and bindings affects the incidence of each type of ski-related injury. - WRONG. Seems to suggest that technology directly impacts but it's not.

(D) If the technology of ski boots and bindings continues to advance, the incidence of ski-related injuries will continue to decline. - WRONG. Just like A this tries to correlate but this is not necessarily true.

(E) Injuries that occurred on the slopes of ski resorts made up a smaller percentage of ski-related injuries in 1980 than in 1950. - CORRECT. If not than our conclusion seems to falter. Thus, this is inferable infact it is an assumption type inferance that has to be true.

Answer E.
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