You give a delivery driver $15.50 for a pizza that costs $12.50. you tell the driver to keep the change as a tip. is the tip more or less than 20%?

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

How can constraints be used to model a real-world situation?

The ratio of the height of two similar cylinders is 4 to 3 what is the ratio of their volumes