Carcass wrote:
Last year a state senate consisting of only Republican and Democrat members had 20 more Republican members than Democrat members. This year the senate has the same number of members as last year, but it has 2 fewer Republican members than last year. If this year the number of Republican members is 2/3 the number of senate members, how many members does the senate have this year?
(A) 33
(B) 36
(C) 42
(D) 45
(E) 48
Let D = the number of Democrats LAST YEAR
Let R = the number of Republicans LAST YEAR
Last year a state senate consisting of only Republican and Democrat members had 20 more Republican members than Democrat membersIn other words: the number of Republicans = (the number of Democrats) + 20
In other words:
R = D + 20This year the senate has the same number of members as last year, but it has 2 fewer Republican members than last year. So, R - 2 = the number of Republicans THIS YEAR
Important: Since the Senate still has the same number of members as last year, there must be 2 additional Democrats this year (to account for the fact there are 2 fewer Republicans).
So, D + 2 = the number of Democrats THIS YEAR
If this year the number of Republican members is 2/3 the number of senate membersImportant: If Republicans account for 2/3 of the senate, then Democrats must account for the remaining 1/3 of senate. Since 2/3 is TWICE 1/3, we can say: (the number of Republicans this year) = 2(the number of Democrats this year).
In other words: R - 2 = 2(D + 2)
Expand the right side: R - 2 = 2D + 4
Add 2 to both sides to get:
R = 2D + 6How many members does the senate have this year? We now have the following system:
R = D + 20R = 2D + 6Since both equations are set equal to R, we can write:
D + 20 = 2D + 6Solve to get:
D = 14To find the corresponding value of R, we can take:
R = D + 20Replace D with 14 to get: R = 14 + 20 = 34
So,
R = 34Since R + D = the total number of senators LAST YEAR, and since the Senate has the same number of members THIS YEAR, we can conclude that:
The total number of Senators THIS YEAR = R + D =
14 +
34 =
48 Answer: E
Cheers,
Brent