1-The average number of electronic messages received in a day on a smartphone is 15. If the standard deviation is known = 4 seconds, what is the probability you will receive between 10 and 20 messages a day?

40%

36%

60%

64%

2-If it takes an average of 10 seconds to download a certain file, what is the probability that the download will take at least 12 seconds?

0.17

0.42

0.58

0.83