SOLVE A number between 10 and 100(two-digit number ) 5 times the sum of the digit is 13 less than the number formed by interchanging the digits. if 3 times the digit at one place is equal to half of the place. find the original number?

Asmall (but heavy) particle placed in a glass of water will follow a zigzag motion because the particle will bounce off of the water molecules it meets. this is called brownian motion. a physicist simulates this on a computer, by varying the distance a particle can travel (called the mean free length), on average, before it collides with a water molecule and assigning the change in motion to be one of 8 directions, each with a similar probability. by running the simulated particle (with the same mean free length) many times she determines that it should take 15 seconds, on average, for the particle to fall to the bottom, with a standard deviation of 1.5 seconds. next she lets a real particle fall through a glass of water and finds that it took 18 seconds. what does she conclude, and why?

Which of the following is correct interpretation of the expression -4+13

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.