Jenny's mom says she has an hour before it's bedtime. Jenny's spends 3/5 of hour texting a friend and 3/8 of the remaining time brushing her teeth and putting on her pajamas. she spends the rest of the time reading her book. how long did jenny read?

First you'll need to get the same denominator. So instead of 3/5 and 3/8 you'll have 24/40 and 15/40. Now that we've changed the value of the denominator, the 40/40 will now represents the 1 hour that Jenny has before bedtime. So you add 24/40 and 15/40 and get 39/40. 39/40 stands for the time that Jenny has already spent brushing her teeth and texting her friend all together. Since the 1 hour is 40/40 subtract 39/40 from it to get 1/40. 1/40 is equal to the rest of the time Jenny spends reading or 1.5 minutes.