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A total of 30 percent of the geese included in a certain migration stu
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01 Mar 2022, 04:00
01 Mar 2022, 04:00
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Question Stats:
46% (03:24) correct
53% (02:38) wrong based on 13 sessions
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A total of 30 percent of the geese included in a certain migration study were male. If some of the geese migrated during the study and 20 percent of the migrating geese were male, what was the ratio of the migration rate for the male geese to the migration rate for the female geese? [Migration rate for geese of a certain sex = (number of geese of that sex migrating) / (total number of geese of that sex)]
A. 1/4
B. 7/12
C. 2/3
D. 7/8
E. 8/7
A. 1/4
B. 7/12
C. 2/3
D. 7/8
E. 8/7
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Joined: 20 Feb 2017
Posts: 2506
Given Kudos: 1053
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Re: A total of 30 percent of the geese included in a certain migration stu
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05 Mar 2022, 02:28
05 Mar 2022, 02:28
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Expert Reply
Let there be g geese, of which 0.3g are male and 0.7g are female
Let's say m geese migrated, 0.2m are male and 0.8m are female
Migration Rate Male = 0.2m / 0.3g = (2/3)*(m/g)
Migration Rate Female = 0.8m / 0.7g = (8/7)*(m/g)
Ratio of migration rates = (2/3) / (8/7) = 7/12
Answer is (B)
Let's say m geese migrated, 0.2m are male and 0.8m are female
Migration Rate Male = 0.2m / 0.3g = (2/3)*(m/g)
Migration Rate Female = 0.8m / 0.7g = (8/7)*(m/g)
Ratio of migration rates = (2/3) / (8/7) = 7/12
Answer is (B)
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Re: A total of 30 percent of the geese included in a certain migration stu
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07 Mar 2022, 11:03
07 Mar 2022, 11:03
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GreenlightTestPrep wrote:
A total of 30 percent of the geese included in a certain migration study were male. If some of the geese migrated during the study and 20 percent of the migrating geese were male, what was the ratio of the migration rate for the male geese to the migration rate for the female geese? [Migration rate for geese of a certain sex = (number of geese of that sex migrating) / (total number of geese of that sex)]
A. 1/4
B. 7/12
C. 2/3
D. 7/8
E. 8/7
A. 1/4
B. 7/12
C. 2/3
D. 7/8
E. 8/7
We can skip algebra and just find some values that satisfy the given information.
A total of 30 percent of the geese included in a certain migration study were male.
So, it could be the case that there where 100 geese in the STUDY, which means 30 were male and 70 were female.
Some of the geese migrated during the study and 20 percent of the migrating geese were male
So it could be the case 10 geese from the study migrated, which means 2 were male and 8 were female.
What was the ratio of the migration rate for the male geese to the migration rate for the female geese?
The migration rate for the males = 2/30 = 1/15
The migration rate for the females = 8/70 = 4/35
So, the ratio of the migration rate for the male geese to the migration rate for the female geese = (1/15)/(4/35)
= (1/15)(35/4)
= 35/60
= 7/12
Answer: B
