At a local election there were two propositions on the ballot, R and S. Twice as many voters voted "yes" for R as for S. If the number who voted "yes" for R but "no" for S was 750 and the number who voted "yes" for S but "no" for R was 310, how many voted "yes" for both propositions? a. 122b. 127c. 130d. 135

c. 130

Step-by-step explanation:

Let call B the quantity of voters who voted yes for both propositions.

From the question we know that twice as many voters voted "yes" for R as for S, that can be written as the following equation:

R+B=2 (S+B)

Where R is the number who voted "yes" for R but "no2 for S and S is the number who voted "yes" for S but "no" for R.

Replacing R by 750 and S by 310 and solving for B, we get:

750+B=2 (310+B)

750+B=620+2B

2B-B=750-620

B=130

So, 130 voters voted yes for both propositions