how much time it will take to visit mutianyu great wall ....

first i want to visit No. 14 watchtower and No. 23 watchtower ...... then i should come down through cable car or i should visit till 6 tower for slide way down .... how much time it will take to visit 14 to 23 tower and from 23 to 6 tower ....... i mean i will reach there at 9.00 am .... but i can stay on the wall till 2 pm .... is this enough time