Can someone just explain what i need to do? i'm so confused the length of a text messaging conversation is normally distributed with a mean of 10 minutes and a standard deviation of 4 minutes. what is the probability that a conversation lasts longer than 20 minutes?

Acoin is tossed twice. let e e be the event "the first toss shows heads" and f f the event "the second toss shows heads". (a) are the events e e and f f independent? input yes or no here: yes (b) find the probability of showing heads on both toss. input your answer here: preview

Antonia and carla have an equivalant percentage of green marbles in their bags of marbles. antonia has 4 green marbles and 16 total matbles. if carla has 10 green marbles , how many total marbles does carla have

Sasha drank 8 bottles of water everyday for a week. how many bottles of water did she drink in total?