If A and B are mutually exclusive events, then P(A or B) = P(A) + P(B). and
If A and B are inclusive events, then P(A or B) = P(A) + P(B) - P(AB).
Si hay 30% de probabilidad de que neve y llueva en día de hoy. Si la probabilidad de
lluvia es 40% y la probabilidad de nieve es de 15%. ¿Cuál es la probabilidad de que caída
nieve o llueva en el día de hoy?

Solve the equation x/4 - 5= -8 -27 -12 -7 12

Someone me i need with this stuff

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.