Bismihi Ta'ala

From amongst the many rewards prepared and promised for the Haafiz of Qur'an, one is ' If a person preserves the Qur'an by memory, and regards its Halaal as Halaal and its Haraam as Haraam (acts upon the teachings of the Qur'an) then he or she will be granted the intercession of ten such people of their family upon whom Hell-fire was destined.'

From this Hadith we come to know that the figure that is certain and determined is ten and not fifty.

And Allah knows best