Final answer:
The range of the linear cost function C(x) = 6x, where x represents the number of items bought in packages of 10 with a maximum limit of 5 packages, is [0, 30].
Step-by-step explanation:
The linear cost function C(x) = 6x gives the cost for buying x items. In this case, the items are sold in packages of 10. To find the range of the function C, we need to determine the minimum and maximum values that x can take. Since no one can buy more than 5 packages, the maximum value of x is 5. Plugging this value into the cost function, we get C(5) = 6 * 5 = 30. Therefore, the range of the function C is [0, 30].