If there are 40 entries to the science fair how man ways can the students get 1st, 2nd, and 3rd

How many $20 bills do you need to have to make $280

Follow these steps using the algebra tiles to solve the equation −5x + (−2) = −2x + 4. 1. add 5 positive x-tiles to both sides and create zero pairs. 2. add 4 negative unit tiles to both sides and create zero pairs. 3. divide the unit tiles evenly among the x-tiles. x =

Which of the following is the shape of a cross section of the figure shown below