(CMR 2020) - Question Medium of Mathematics

A store decides to reward its customers. Each customer will receive one of the six possible gifts available, according to their arrival order at the store. The gifts to be distributed are: a ball, a keychain, a pen, a soda, an ice cream, and a CD, in that order. The first customer at the store receives a ball, the second receives a keychain, the third receives a pen, the fourth receives a soda, the fifth receives an ice cream, and the sixth receives a CD. The seventh receives a ball, the eighth receives a keychain, and so on, according to the order of the gifts. The one-thousandth customer will receive as a gift a:

In a school presentation, eight friends, including Carlos, Timóteo, and Joana, line up. Calculate the number of different ways this line of friends can be formed so that Carlos, Timóteo, and Joana always stay together:

Consider the linear system below: 2x + 3y = 10 5x - 4y = -7 Transform this linear system into a matrix form using a matrix A and a column vector X, representing the unknowns. Write down the resulting matrix equation and inform what is the dimension of matrix A.

The Science class is learning about vegetable gardens and decided to plant a small rectangular garden at school, where they will grow lettuce and carrots. The garden's rectangle measures 3 meters in length and 2 meters in width. To find out how many plants will fit in the garden, they need to calculate the perimeter. Help the students calculate the perimeter of this rectangular garden.