Jessica wants to take three books on vacation with her. she has five books to choose from. how many possible combinations of three books could she take on vacation?

2-digit numbers less than 91 which are 1 less than a multiple of 10

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.

Solve the triangle. a = 21°, c = 105°, c = 5