The answer to your question is 25 minutes.
An hour is 60 min so 1/3 of that would be 20 min. which is how long Jenny spent texting her friend. 1/4 would be 15 min in which she spent brushing & putting on pajama's. If she spent the rest of her hour reading that means she must of read for 25 min, which you could find out by adding the 20 and 15 min she's already spent and then subtracting it from the total time 60 min
1/3 of an hour=20 min
1/4 of an hour=15 min
20 min+15 min= 35 min
60 min-36 min= 25 min
Hope this helps! :)
