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Re: Researchers studying long-term changes in regional mouse populations h
[#permalink]
20 Apr 2024, 14:21
20 Apr 2024, 14:21
On the first table you have the numerator and second one gives you the fraction. Question stem is about total mouse population which is about the denominator. So depending on how the numerator (species X, first table) and the fraction ( bottom table) we need to work out the answers.
The total mouse population of TY changed more from 1960 to 1975 than from 1975 to 1990.
numerator change is roughly the same between these years. % change is (3.4/.4=8) and (2/.4=5) between the years. Thus fraction decreases more in 60-75 than it increases in 75-90. Total population (denominator) must have decreased more in 60-75.
Rounded to the nearest million, the total mouse population of TY was 47 million in 1990.
(968/2%)=47m
The total mouse population of TY fell from 1975 to 1990.
numerator increases by (968/144)= 7 times whereas fraction increases by 5 times. Thus denominator should have increased. Total population couldnt have decrease because then the fraction will become greater than 7. In fact the population should have increased by 7/5=1.2 times roughly).
region's total mouse population exceeded 50 million in 1975
IQ (1m=1%, 100% = 100m)
PS(162K=0.4% 250*162K=40.5m =100%)
The total mouse population of TY changed more from 1960 to 1975 than from 1975 to 1990.
numerator change is roughly the same between these years. % change is (3.4/.4=8) and (2/.4=5) between the years. Thus fraction decreases more in 60-75 than it increases in 75-90. Total population (denominator) must have decreased more in 60-75.
Rounded to the nearest million, the total mouse population of TY was 47 million in 1990.
(968/2%)=47m
The total mouse population of TY fell from 1975 to 1990.
numerator increases by (968/144)= 7 times whereas fraction increases by 5 times. Thus denominator should have increased. Total population couldnt have decrease because then the fraction will become greater than 7. In fact the population should have increased by 7/5=1.2 times roughly).
region's total mouse population exceeded 50 million in 1975
IQ (1m=1%, 100% = 100m)
PS(162K=0.4% 250*162K=40.5m =100%)
Re: Researchers studying long-term changes in regional mouse populations h
[#permalink]
26 Apr 2024, 10:44
26 Apr 2024, 10:44
3
Kudos
horrorslive wrote:
Can anyone please explain q2 and @Sajjid1994 please provide the official explanation.
For Q.2
Two Conditions need to be satisfied :
1. Species X population decreased from 1960 to 1975
2. The region's total mouse population exceeded 50 million in 1975
Observe condition one for all three
You can see that
For JR there is an increase so no need to check condition 2.
Ans: No
For IQ and PS there is a decrease.
Condition 2
Total Population= (Species*100)/Percentage of total mouse population
Use Calculator
For IQ
Total Population in 1975 = 92834000/0.707=131,306,930 >50 Million
Ans: Yes
For PS
Total Population in 1975=16204000/0.385=42,088,311<50 Million
Ans: No
Hit Kudos if you found the explanation useful.
Re: Researchers studying long-term changes in regional mouse populations h
[#permalink]
28 May 2024, 01:43
28 May 2024, 01:43
Q2. or each of the following regions, select Yes if the region's Species X population decreased from 1960 to 1975 AND the region's total mouse population exceeded 50 million in 1975, Otherwise, select No,
To answer this question, we need to check two conditions for each region (IQ, JR, PS):
1. The region's Species X population decreased from 1960 to 1975.
2. The region's total mouse population exceeded 50 million in 1975.
Analysis:
1. *Region IQ:*
- Species X population in 1960: 1,859,460
- Species X population in 1975: 928,340
- Decrease from 1960 to 1975: Yes
- Total mouse population in 1975: To find the total mouse population in 1975, use the percentage data.
- Percentage of Species X in 1975: 0.707%
- Total mouse population in 1975: \( \frac{928,340}{0.707\%} \approx 131,294,911 \)
- Total mouse population > 50 million: Yes
Answer: *Yes*
2. *Region JR:*
- Species X population in 1960: 21,900
- Species X population in 1975: 24,590
- Decrease from 1960 to 1975: No
Answer: *No*
3. *Region PS:*
- Species X population in 1960: 219,670
- Species X population in 1975: 162,040
- Decrease from 1960 to 1975: Yes
- Total mouse population in 1975: To find the total mouse population in 1975, use the percentage data.
- Percentage of Species X in 1975: 0.385%
- Total mouse population in 1975: \( \frac{162,040}{0.385\%} \approx 42,087,013 \)
- Total mouse population > 50 million: No
Answer: *No*
### Summary of Answers:
- IQ: *Yes*
- JR: *No*
- PS: *No*
To answer this question, we need to check two conditions for each region (IQ, JR, PS):
1. The region's Species X population decreased from 1960 to 1975.
2. The region's total mouse population exceeded 50 million in 1975.
Analysis:
1. *Region IQ:*
- Species X population in 1960: 1,859,460
- Species X population in 1975: 928,340
- Decrease from 1960 to 1975: Yes
- Total mouse population in 1975: To find the total mouse population in 1975, use the percentage data.
- Percentage of Species X in 1975: 0.707%
- Total mouse population in 1975: \( \frac{928,340}{0.707\%} \approx 131,294,911 \)
- Total mouse population > 50 million: Yes
Answer: *Yes*
2. *Region JR:*
- Species X population in 1960: 21,900
- Species X population in 1975: 24,590
- Decrease from 1960 to 1975: No
Answer: *No*
3. *Region PS:*
- Species X population in 1960: 219,670
- Species X population in 1975: 162,040
- Decrease from 1960 to 1975: Yes
- Total mouse population in 1975: To find the total mouse population in 1975, use the percentage data.
- Percentage of Species X in 1975: 0.385%
- Total mouse population in 1975: \( \frac{162,040}{0.385\%} \approx 42,087,013 \)
- Total mouse population > 50 million: No
Answer: *No*
### Summary of Answers:
- IQ: *Yes*
- JR: *No*
- PS: *No*
