Although large mammals like elephants and whales tend to live longer

Question

Although large mammals like elephants and whales tend to live longer than small ones like mice, larger breeds of dogs have shorter life spans, on average, than smaller breeds. A researcher studying the relationship between average body mass and average life span in breeds of dogs concluded that, for every 2 kilograms of body mass, life span is 1 month less. According to this conclusion, the average life span of a breed with an average body mass of x kg is y months less than the average life span of a breed with an average body mass of 10 kg.

Select for x and for y values that are jointly consistent with the information provided. Make only two selections, one in each column.

Show Spoiler

Attachment:

DI - 6.png

Pro tip: Combine official questions for familiarity with GMAT Club Tests for analytics and tougher Focus-level practice so the real exam feels manageable. Explore →

KLSVGMAT · Accepted Answer

For every extra 2 kg, the life span decreases by 1. Let's say one breed's weight is 13 kg and the other one's is 9 kg. The difference is 4 kg, so the life span will decrease by 2 months. If the difference is 6 kg, the life span decrease is 3 months and so on...

Now, the weight is x kg and the other one is 10 kg. The difference is (x-10) kg. And y = (x-10)/2. So, x is an even number - 20 or 30. The only right answer here x=30 and y= (30-10)/2 = 10.

yikes000 · Answer

Hey  Sajjad1994  can you post the explanation? thanks!

nyota.benson · Answer

Yeah this would need an explanation.

chetan2u · Answer

Select for x and for y values that are jointly consistent with the information provided. Make only two selections, one in each column. 
These type of questions are quite regular in focus edition test. The wording tells us that there are various possibilities for x and y, and just one of them is in option.

Only way to do this is by finding the  relation   between x and y.

x: Average life body mass
y: Difference in life span

For every increase in 2kg mass, life span decreases by 1 month. 
So (Mass increase)= M_1-M_2=2y  
Now mass is increasing from 10 to x, so 
 M_1-M_2=x-10=2y  
 x=2y+10

We can check options now. 
x is surely even and larger than y. 
so x can be 30 or 20
x=20: 20=2y+10 or y=5…..Not in options
x=30: 30=2y+10 or y=10…..Yes

Answer:
y=10
x=30

sayan640 · Answer

For every 2 kgs , life span is 1 month less.

Hence , for every extra 10 kgs , life span 10/2 = 5 months less.

But see , y is not 5 in any of the options.

Hence , x=10 + 10 = 20 can be ruled out.

Try with x= 30 , In that case the extra will be = 30 -10 = 20 kgs ( Since we are comparing with a 10 kg breed)

Hence , for every extra 20 kgs , life span will be 20/2 = 10 months less.

y=10 ; x= 30

Note you cant try with x=15 or 25 as they are not even divisible by 2 and no option in y is given in decimals.
 GMATinsight

HarshZsssh · Answer

is there any trick to solve these kind of ques like at first glance my mind stop working after seeing the question how can i solve this but after seeing ur it felt lott easier

MartyMurray · Answer

Although large mammals like elephants and whales tend to live longer than small ones like mice, larger breeds of dogs have shorter life spans, on average, than smaller breeds. A researcher studying the relationship between average body mass and average life span in breeds of dogs concluded that, for every 2 kilograms of body mass, life span is 1 month less. According to this conclusion, the average life span of a breed with an average body mass of x kg is y months less than the average life span of a breed with an average body mass of 10 kg.

Select for x and for y values that are jointly consistent with the information provided. Make only two selections, one in each column.

Show Spoiler

Attachment:

DI - 6.png

Select for x and for y values that are jointly consistent with the information provided. Make only two selections, one in each column.

Find the relationship between  x  and  y

From the passage:

for every 2 kilograms of body mass, life span is 1 month less

So, with regard to specifics of the question, for every 2 kilograms of body mass over 10 kilograms, the lifespan will be 1 month less than the lifespan of a breed with a body mass of 10 kilograms.

Thus, the relationship between  x  and  y  is the following:

\frac{x - 10}{2} = y

Find two values in the list that fit the relationship

10

15

20

25

30

35

Since  \frac{x - 10}{2} = y ,  x = 2y + 10 .

The smallest possible  y  is  10 . So, the smallest possible  x  is  2(10) + 10 = 30 .

\frac{30 - 10}{2} = 10

We see that  x = 30  and  y = 10  fit the relationship.

Correct answer:   30 ,  10

DonBosco7 · Answer

Although large mammals like elephants and whales tend to live longer than small ones like mice, larger breeds of dogs have shorter life spans, on average, than smaller breeds. A researcher studying the relationship between average body mass and average life span in breeds of dogs concluded that, for every 2 kilograms of body mass, life span is 1 month less. According to this conclusion, the average life span of a breed with an average body mass of x kg is y months less than the average life span of a breed with an average body mass of 10 kg.

Select for x and for y values that are jointly consistent with the information provided. Make only two selections, one in each column.

Show Spoiler

Attachment:

DI - 6.png

I solved it as such:
1] given that for every 2 kilograms of body mass, life span is 1 month less:- this line essentially gives you the ratio between BM (body mass) and LS (life span)

---------> hence BM/LS = 2/1

2] According to this conclusion, the average life span of a breed with an average body mass of x kg is y months less

----------> can be written as BM/LS = x/y

3] But additional info added to the above statement is that of a comparison or difference with a breed having a body mass 10 kg

----------> can be written as BM/LS = x-10/y

----------> x-10/y = 2/1

----------> x-10 = 2y

Now check the option for x and y

----------> 30-10 = 2(10)

hence, x = 30 & y = 10

adi007 · Answer

Its simple when thinks in terms of equation. 
2 kg -> a - 1(month)
a is just the constant from which we will subtract 1 month.
10 kg = a - 5 
x = (a-5) - y (via 10kg case) = a - x/2 (via x case) 
 x = 10 + 2 y ( Final equation) 
Now just check which solution satisfy this equation. 
x = 30 and y = 10 Ans

Dereno · Answer

Initial few statements are given to minimise the valuable time of yours on the D day.

Let’s jump into the crux directly.

Average body mass and average life span is related, but with an inverse relationship.

For, 2 Kg = drop is 1 month

Let’s focus on the last line alone.

For, 10 Kg = ?

By unitary method, ? = (10*1)/2 = 5 month.

So, we have now two data’s,

2 Kg. ————- 1 month

10 kg. ————- 5 month.

And, in question we are given x kg. So, let’s fix it in the equation.

2 Kg. ————- 1 month

x kg. ————- a month

10 kg. ————- 5 month.

given that : “ the average life span of a breed with an average body mass of x kg is y months less than the average life span of a breed with an average body mass of 10 kg .“

y = a - 5

From this two equations, we get

2 Kg. ————- 1 month

x kg. ————- a month

a = (x*1)/2

a= x/2

Substitute in y = a-5, we get

y = (x/2) - 5

x = 2y+10

If y = 10, then x =30

tryorcry · Answer

Avg Mass:Life span is 2:1

Average mass = (difference in mass compared to 10 kg dog)

(30-10)=20

20 mass shortens 10 months

hence, x=30 , y=10

minininini · Answer

Great ques!

Although large mammals like elephants and whales tend to live longer

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

GMAT Two-part Analysis (TPA) Questions

Although large mammals like elephants and whales tend to live longer

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia