How to solve x - 9 = 8 ?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

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?

When rolling 26 sided number cube what are the chances some of the role will be seven