A rally starts with 120 members. Each hour, 9 members drop out of the group. How many members will remain after 1, 2, 3, $\dots$ hours? Find a linear expression to represent the number of members at the end of the $n^{\text{th}}$ hour. [Page No. 24]

Initial member in rally = 120

Number of members drop out every hour = 9

After 1 hour, number of members = 120 - 9 = 111

After 2 hour, number of members = 111 - 9 = 102

After 3 hour, number of members = 102 - 9 = 93

Hence, linear expression of number of members after $n^{\text{th}}$ hour = 120 - 9n.