Question

The U.S. senate is composed of 2 senators from each of the 50 states. In order for a treaty to be ratified, at least two thirds of the senators present must approve the treaty. Suppose all senators are present and 48 of them have voted in favor of a treaty. What are the possible numbers of additional senators who must vote in favor of the treaty in order to radify it?

Answer 1

"at least two thirds of the senators"
at least 2/3 of 100 senators is 67 senators.
So you need at least 67 senators in favor of the treaty in order to ratify it.
48 have already voted in favor of the treaty.
So we need at least 67 - 48 = 19 additional senators who must vote in favor of the treaty.

Answer 2

"at least two thirds of the senators" at least 2/3 of 100 senators is 67 senators. So you need at least 67 senators in favor of the treaty in order to ratify it. 48 have already voted in favor of the treaty. So we need at least 67 - 48 = 19 additional senators who must vote in favor of the treaty