Answer:
At least 67 votes
Explanation:
We were given the following information:
There are 100 senators in the US senate,
At least 2/3 of them vote yes in order to ratify or approve, a treaty
The least number of votes needed is calculated below:
[tex]\begin{gathered} x\ge\frac{2}{3}(100) \\ \text{Expand the bracket, we have:} \\ x\ge66.6667 \\ x\ge67 \\ \\ \therefore x\ge67 \end{gathered}[/tex]Therefore, they must have at least 67 votes to ratify a treaty