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In a farm, the ratio of pigs to chickens is 13 to 28. When [#permalink]
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28 Oct 2012, 23:01
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In a farm, the ratio of pigs to chickens is 13 to 28. When 15 pigs were added to the farm, the ratio of pigs to chickens became 4 to 7. What was the original total number of pigs and chickens in the farm? (A) 200 (B) 205 (C) 210 (D) 215 (E) 220 I suppose that, [13][/28] + 15 pigs can be [16][/28] to reduce the fraction we probably will receive [4][/7], so 3 in numrator is equal  15 pigs the total number of pigs before new comers = 13*5=75
how can I get the number of chickens?
Thanx
Last edited by actleader on 29 Oct 2012, 22:54, edited 2 times in total.



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Re: Arithmetic In a farm, the ratio of pigs to chickens is 13 to [#permalink]
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28 Oct 2012, 23:11
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actleader wrote: Hi! Could you help me with tne next problem solving question.
In a farm, the ratio of pigs to chickens is 13 to 28. When 15 pigs were added to the farm, the ratio of pigs to chickens became 4 to 7. What was the original total number of pigs and chickens in the farm?
I suppose that, [13][/28] + 15 pigs can be [16][/28] to reduce the fraction we probably will receive [4][/7], so 3 in numrator is equal  15 pigs the total number of pigs before new comers = 13*5=75
how can I get the number of chickens?
Thanx Pigs:Chicken = 13:28 No of pigs = 13x, No of chicken = 28x When 15 more pigs were added, ratio becomes 4:7 i.e. \(\frac{(13x+15)}{28x} = \frac{4}{7}\) x = 5 Initially, the no of pigs was 13x = 13*5 = 65 No of chicken was 28x = 28*5 = 140 Original total = 205 or Original total = 13x + 28x = 41x = 41*5 = 205
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Re: In a farm, the ratio of pigs to chickens is 13 to 28. When [#permalink]
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29 Oct 2012, 01:29



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Re: In a farm, the ratio of pigs to chickens is 13 to 28. When [#permalink]
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03 Nov 2012, 09:13
Bunuel wrote: actleader wrote: In a farm, the ratio of pigs to chickens is 13 to 28. When 15 pigs were added to the farm, the ratio of pigs to chickens became 4 to 7. What was the original total number of pigs and chickens in the farm? I suppose that, [13][/28] + 15 pigs can be [16][/28] to reduce the fraction we probably will receive [4][/7], so 3 in numerator is equal  15 pigs the total number of pigs before new comers = 13*5=75
how can I get the number of chickens?
Thanx Similar questions to practice; twonumbersareintheratio56if22isaddedtothe135168.htmlaphysicsclasshasmajorsandnonmajorsinaratioof4to133685.htmltheratiooftwopositivenumbersis3to4ifkisadded95198.htmlHope it helps. VeritasPrepKarishma, Bunuel thanx for solving the problem but I'd like yo know how can I found the number of chickens when I deducted that 3 in numerator is equal  15 pigs?



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Re: In a farm, the ratio of pigs to chickens is 13 to 28. When [#permalink]
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03 Nov 2012, 21:53
actleader wrote: VeritasPrepKarishma, Bunuel thanx for solving the problem but I'd like yo know how can I found the number of chickens when I deducted that 3 in numerator is equal  15 pigs?
Yes, when you say that the the additional 3 is actually 15, you get 5 as the multiplier. In your solution above, you wrote: "the total number of pigs before new comers = 13*5=75" which should actually be "the total number of pigs before new comers = 13*5=65" (calculation error) Next, no of chickens will be 28*5 = 140 (after all, you have already found that the multiplier of the ratio is 5. You multiplied 13 by 5 to get the number of pigs. You multiply 28 by 5 to get the number of chickens)
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Re: In a farm, the ratio of pigs to chickens is 13 to 28. When [#permalink]
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actleader wrote: In a farm, the ratio of pigs to chickens is 13 to 28. When 15 pigs were added to the farm, the ratio of pigs to chickens became 4 to 7. What was the original total number of pigs and chickens in the farm? (A) 200 (B) 205 (C) 210 (D) 215 (E) 220 I suppose that, [13][/28] + 15 pigs can be [16][/28] to reduce the fraction we probably will receive [4][/7], so 3 in numrator is equal  15 pigs the total number of pigs before new comers = 13*5=75
how can I get the number of chickens?
Thanx 15sec approach to solve this question: Original ratio is 13:28, which shows the original total must be a multiple of 41. Only 205 among answer choices is multiple of 41. Ans B it is. Further, since you are interested in finding number of chickens too..Once you've total number, you can deduce number of chickens, pigs and everything else since you've the ratio given.
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