math
posted by YASMINE .
atrtie and Billy both shop at the same local grocery store between 5 and 6 in the evening.The last time they saw each other was on Tuesday.Artie shops every five days and Billy shops every days.What day of the week will they next run into each other, assuming that the store is open 7 days a week?

Billy shops every how many days? You left out an important piece of information.