In the town of Xionia, elections were held every 5 years, between the year 2000 to the year 2020. During the 5 elections held in this period, the number of female voters increased while the number of male voters decreased from 3300 in the year 2000.
In the given expressions, F and M represent the percentage change in the number of female and male voters, respectively, over the 5 elections, and R represents the ratio of female to male voters in the year 2000. The percentage change in voters is calculated as \(\frac{(number of new voters – number of old voters)}{(number of old voters)}\) * 100
Select the expression that represents the number of female voters in the year 2000, and select the expression that represents the ratio of female to male voters in the year 2020. Make only two selections, one in each column.
Solution:In 2000
No. of male voters = 3300
Let No. of female voters = x
Since R is the ratio of No. of Female voters to No. of male voters in 2000
Thus, R = x / 3300
x = 3300R
In 2020
Let No. of male voters = A
Let No. of female voters = B
Also, % change in male voters = M
% change in female voters = F
Since M = \(\frac{(number of new voters – number of old voters)}{(number of old voters)}\) * 100
Thus, M = \(\frac{(A - 3300) }{ 3300}\) * 100
Since no. of male voters decreased in 2020, we will take into account the sign change in the numerator
Thus, M = \(\frac{(3300 - A) }{ 3300}\) * 100
Thus A = 3300 - 33M
Also, F = \(\frac{(number of new voters – number of old voters)}{(number of old voters)}\) * 100
Thus, F = \(\frac{(B - 3300R) }{ 3300R}\) * 100
B = 33RF + 3300R
We need to find the ratio of female voters to male voters in 2020
i.e., \(\frac{B}{A}\) = \(\frac{(33RF + 3300R) }{ (3300 - 33M)}\)
\(\frac{B}{A}\) = \(\frac{33R(F + 100) }{ 33(100 - M)}\)
\(\frac{B}{A}\) = \(\frac{R(100 + F) }{ (100 - M)}\)
- No. of Female voters in 2000 = 3300R
- Ratio of Female voters to Male voters in 2020 = \(\frac{R(100 + F) }{ (100 - M)}\)
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