Can someone help me please?

Amber had 1/6 of a pie left after the bake sale. rihanna had 3/8 of a pie left. what fraction of a pie did they have altogether?

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.

△def is similar to △stu. write a proportion that contains st and su.