john types 20 pages in 40 min, sue types 20 pages in 30 min, bob types 20 pages in 24 min. working togehter how long to type 20 paqes

Answer 1

john types 20/40 or 1/2 page/min
Sue types 20/30 or 2/3 page/min
Bob types 20/24 or 5/6 page/min

combined rate = 1/2 + 2/3 + 5/6 or 2 pages per minute

time at combined rate = 20/2 or 10 minutes