Rebecca had a piece of ribbon. she used 3/8 of it to tie a parcel. she used 1/5 of the remainder for a bookmark. rebecca had 24 centimeters of ribbon left. what was the length of ribbon rebecca had at first?

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?