If a coin is flipped 20 times and a head comes up 13 times, what is the relative frequency of a head coming up?

Look at arnold's attempt to solve the equation for b: 3b = 12 b = 3 · 12 b = 36 describe the mistake that arnold made.

Se tiene en una caja de canicas 10, 4 blancas y 6 negras ¿cual es la probabilidad que en 2 extracciones con reemplazo sean blancas? ¿cual es la probalidad que en 2 extracciones sin reemplazo sean negras?

The high temp today was 62°. when nighttime comes, the temp will drop 40°. by 4am the temp will drop an additional 40°. what is the temp at 4am?