Igot the last 3 problems correct and then my mind went blank

daniel is 4 times as old as jessica and is also 15 years older than jessica.

how old is jessica?

Q1) jin loves carrot yesterday she ate ½ of here carrots and today she ate 2/3 of the remaining carrots. she then discover that she has 12 carrots left. yesterday she must has started with carrots? a)36 b)48 c)60 d)72

Monitors manufactured by tsi electronics have life spans that have a normal distribution with a standard deviation of 1800 hours and a mean life span of 20,000 hours. if a monitor is selected at random, find the probability that the life span of the monitor will be more than 17,659 hours. round your answer to four decimal places.

Zack and tia played chess for 50 min they put the chessboard away at 11: 20 when did they start