In April 1846 how many family is left to lead to a new life beyond the Rocky Mountains

Not sure if this answers the question, but 83 members of the Donner party who were trapped in the mountains, 45 only survived to reach California.

the correct answer is the following is a list of inventions made in the medieval islamic world, especially during the "islamic golden age" (8th to 13th centuries),[1][2] as well as the late medieval period, especially in the emirate of granada and the ottoman empire.

science and technology in the islamic world adopted and preserved knowledge and technologies from contemporary and earlier civilizations, including persia, india, china, and greece-roman antiquity, while making a number of improvements and innovations.