Every 3 days seth goes to the grocery store. his best friend brian goes every 5 days. on what day will both go to the store on the same day

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.