How many solutions does the equation 4n + 6 = 4 + 2 + 4n have?

two
infinitely many
none
one

Which is the correct excel formula for the 80th percentile of a distribution that is n(475, 33)? =norm.dist(80,475,33,1) =norm.inv(0.80,475,33) =norm.s.inv((80-475)/33)?

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15

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?