A brand of light bulbs has a mean lifetime of 1,500 hours and a standard deviation of 150 hours. A sample of 100 light bulbs gave a mean lifetime of 1,400 hours. What is the margin of error for the sample?

Carli has 90 apps on her phone. braylen has half the amount of apps as theiss. if carli has three timesthe amount of apps as theiss,how many apps does braylen have? let b represent the number of braylen's apps and t represent the number of theiss's apps.