Eighteen people are in a room. What is the minimum number of handshakes to occur to guarantee that everyone has shaken everyone else's hand?

Acompany is testing in comparing to lightbulb designs the box plot shows the number of hours that each lightbulb design last before burning out which statement is best supported by the information of the plot

Which math sentence can be used to determine if the triangle is a right triangle?

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling