The ratio of divorces to marriages has increased since 1940. Therefore

Question

The ratio of divorces to marriages has increased since 1940. Therefore, there must be a greater proportion of children living with only one natural parent than there was in 1940.

Which of the following, if true, most strongly weakens the inference drawn above?

(A) The number of marriages entered into by women twenty-five to thirty-five years old has decreased since 1940.
(B) When there is a divorce, children are often given the option of deciding which parent they will live with.
(C) Since 1940 the average number of children in a family has remained approximately steady and has not been subject to wide fluctuations.
(D) Before 1940 relatively few children whose parents had both died were adopted into single-parent families.
(E) The proportion of children who must be raised by one parent because the other has died has decreased since 1940 as a result of medical advances.

Sparta_750 · Answer

OA (E)

Medical advances have increased life expectancy of parents (net effect). The proportion of children being raised by one parent have decreased as a result. This decrease 'can' set off any rise in the number of children being raised by a single parent because of rise in divorce rates.

carcass  there is a typo in option (e) - di~d. At first I thought it was short form for divorced.

Posted from my mobile device

ARIEN3228 · Answer

Conclusion :Therefore, there must be a greater proportion of children living with only one natural parent than there was in 1940.

While solving strengthen or weaken questions, ask yourself one question every time you look at the options A through E.

Will this given statement strengthen or weaken the given conclusion? This will help you stay inline with the conclusion given.

Two good contenders here are C and E, A B D are irrelevant.

(C) Since 1940 the average number of children in a family has remained approximately steady and has not been subject to wide fluctuations. This option tells us that there has not been a drastic increase or decrease in the number of children in a family. Does this affect the argument in anyway?  it doesn't strengthen or weaken.

THEREFORE option E is correct by P.o.E

arvind910619 · Answer

Hi my friend

Why A is wrong. 
Ratio= Divorce/ Marriage. Option A suggests that the number of marriage has decreased. This would imply that the ration has increased as denominator decreased.
Please help me in this question. 
How did you eliminate A?
Please give your reasoning to eliminate A and support for E.

Thanks in advance,
Arvind

Sparta_750 · Answer

Hi  arvind910619

Proportion of children with single parent = children with single parent / children with both parents

Now let's come to (A). Even if less marriages are happening in one age group, we do not know about other age groups(whether increasing or decreasing since 1940s). Another thing is that proportion of children with single parents depend upon , hold your breath, children with parents.

Eg: consider two scenarios

2010: 
No of marriages: 100
No of children from these marriages: 30
No of divorce of parents who had children: 6
Proportion of children with single parent = 6/30 (and not 6/100) = 20%

2020:
No of marriages: 80
No of children from these marriages: 30
No of divorce of parents who had children: 9
Proportion of children with single parent = 9/30 = 30%

So even with lesser number of marriages, proportion of children with single parent can increase or decrease depending on divorce rates in those couples who have children (not those who are just married)

In short (A) doesn't mention any effect that absolute number of marriages can have on proportion of either children or divorces. It could have been a contender (albeit a weak one!) if there were some information to this effect.

Hope this helps.

Carcass · Answer

From the sentence it was pretty clear the word was "died". However, thank to pointed out Regards

arvind910619 · Answer

Thanks for the prompt response mate.
A very good explanation. 
Kudos for you

kkhushi · Answer

hi actually I'm bit confuse between d and e the statement states that the ration of divorce has increased since 1940 which leads to the greater no. of children living with single parent only.
and option d clearly states that children before 1940 still living with one parent only, isn't this weakening the author's argument that before 1940 children still were living with only single parent whereas option e states that that children living with one parent bc the parent has died and has decreased since 1940. If it was written increase i would have gone with option E. Please address this once

kntombat · Answer

AndrewN ,  IanStewart , I would love to hear your take on this question.
I had narrowed it down to A and E but chose A.

AndrewN · Answer

Hello, everyone. In the interest of assisting the community, I will post my thoughts on the entire question, passage and all. First off, we know from the question stem that we are looking to  weaken  the conclusion. What does this short passage have in store for us?

Okay, this could not be any more direct. A  ratio of divorces to marriages has increased  since a certain point in time, and, based on this ratio, the conclusion is put forth that there must be an accompanying increase in the  proportion of children living with only one natural parent  since that time.

As an aside, any time I see quant words such as  ratio  and  proportion , I become more interested in qualifying actual  numbers  of something, since a ratio may not present a clear enough picture. Anyway, enough of Quant for now.

This one starts out promising enough, drawing attention to  the number of marriages , but without more information about this particular group of women, we cannot say that this consideration brings enough to the table to do anything to the argument, weaken or otherwise. Does this group comprise the largest proportion of women entering into marriages, and has this been the case since 1940? What about the  total  number of marriages to serve as a comparison between the year 1940 and whatever year the present may be? We cannot say anything for sure, and that is a real problem.

This should be an easier elimination. First off, watch out for language that narrows or restricts the applicability of the information that follows. A common CR trap is to restrict information to the point that the test-taker  assumes  something will be true when that may not be the case. Remember, the passage only provides information about divorce as part of a ratio, so now we are working with a sliver of information within that larger framework. In any case, whether children choose one parent or the other is beside the point. We have nothing to lean on in the way of a comparison between 1940 and the present to shed light on the conclusion.

We have seen a ratio and a proportion up to this point, and now we are fed information on an  average , too. All three of these mathematical terms provide vague information until we get some sort of definitive number or total to anchor them to. Sure, it can be tempting to  assume  that if the average number of children has remained steady, it should be true that if the divorce rate is increasing, more children will live in single-parent homes. But now that we are getting into averages, we might reasonably ask ourselves which families are the ones getting broken up, those with no children or maybe one child, or those with five, perhaps. That is, it could or could not be true that an increase in the divorce-to-marriage ratio, paired with a steady  average  number of children  per family  (not necessarily per broken family), would lead to the conclusion given in the passage. Once again, we cannot make that call without further information.

The conclusion specifies children living with one  natural parent —i.e. a biological parent. This answer choice has us focusing on a different group of children altogether, those with no surviving biological parents. Furthermore, adoption is entering into the picture unnecessarily. If the argument is based on natural parents, then we should get an answer choice that is centered on natural parents. Finally, just because we get information on conditions  before 1940 , can we assume anything about the present, relative to the conclusion of the passage? This one misses the mark.

Okay, we have a new proportion to consider here, one between households with two biological parents and those with single parents, and we need to consider this proportion twice over, once for conditions in 1940, once in the present. In 1940, single-parent homes as a result of the death of a spouse/parent were more prevalent than at present. Does this necessarily weaken the conclusion that  there must be a greater proportion of children living with only one natural parent than there was in 1940 ? No. But at the same time, it has introduced another factor to consider in the year-to-year comparison. Perhaps divorce and marriage rates between the two time periods have less to do with the proportion of children living in single-parent households than we were initially led to believe. This information  could  weaken the  inference drawn  in the passage, and we are only asked to find the answer choice that  most strongly weakens  the conclusion. Compare this one to the others on a few criteria:

Incorporates a period-to-period comparison  √  (unlike (B) or (D))   Focuses on children living with one natural parent  √  (unlike (A), (C), or (D))

That is really as far as we need to go. Again, (E) is not proof positive that the conclusion is wayward, but it does the best job of the five answer choices presented diminishing the force of the evidence that would allow someone to make the inference in question. For this reason, we should feel comfortable getting behind it as the answer.

I hope that helps. Good luck with your studies.

- Andrew

Crytiocanalyst · Answer

(A) The number of marriages entered into by women twenty-five to thirty-five years old has decreased since 1940.
Thia will inturn increase the ratio lending support to the argument

(B) When there is a divorce, children are often given the option of deciding which parent they will live with.
This too strengthens

(C) Since 1940 the average number of children in a family has remained approximately steady and has not been subject to wide fluctuations.
If everything is steady and divorce increases single parentership will also increase

(D) Before 1940 relatively few children whose parents had both died were adopted into single-parent families.
now soce the adpotation has increased therefore single parentership will increase

(E) The proportion of children who must be raised by one parent because the other has died has decreased since 1940 as a result of medical advances.
If advancement in medicine has helped parents to survive then it will reduce single parentship this surely weakens 
Therefore IMO E

The ratio of divorces to marriages has increased since 1940. Therefore

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The ratio of divorces to marriages has increased since 1940. Therefore

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