CONCEPT: The question tests on the abilities to frame and solve algebraic equations.

SOLUTIONS:

Let D = the number of Democrat senators last year

Then D + 20 = the number of Republican senators last year,

As the total members remain same;

The number of Democrat senators this year 

=D+2 (These are the 2 Republican Members who turned Democratic)

Thus, the number of Republican senators this year

 = Number of Republican senators last year + 2

 (D + 20) - 2 

= D + 18   (The two members have been moved from Republic to Democrat)

Total Senate Members this year

= Republic + Democrat

 = (D+18) + (D+2) = 2D+20

Thus according to question,

(D + 18)  [Republic Members this year]

= (2/3) (2D+20)  [Total Senators this year]

 
3(D + 18) = 2(2D + 20)

3D + 54 = 4D + 40

14 = D

 Therefore, the total number of senators this year is 2(14) + 20 = 48.(Option E)