For example, thousands have tried to conquer Mount Everest. Of those who make the attempt, only one in seven make it to the top.
In the second sentence, why the verb 'make' isn't 'makes'?
It seems that subject is 'only one',which is singular.
Did I misunderstand the whole sentence?
If there are exception for this, what else would be?
The whole paragraph is here.
Anything worth having takes time. “What we obtain too easily, we esteem too lightly,” Thomas Paine wrote. But in addition to hard work and the occasional long wait or detour through the wilderness, a key ingredient is vision. For example, thousands have tried to conquer Mount Everest. Of those who make the attempt, only one in seven make it to the top. One of the greatest factors in success versus failure is the climbers’ ability to see where they are headed. When storms blow in and obscure the top of the mountain, the climbers grow discouraged and despondent and consider retreat. But when storm air clears and the climbers see the peak again, the journey becomes easier, commitment renews, and faith is strengthened. Suddenly, getting there feels possible.