A truck delivered n number of boxes weighing 20 pounds and t number of boxes weighing 30 pounds to a warehouse. The equation w = 20n + 30t can be used to determine the total weight w, in pounds, of the boxes. If the total weight of the boxes delivered was 480 pounds and 12 boxes weighed 30 pounds, how many boxes weighed 20 pounds?
Maps to Category 15 of the book.
Answer posted on 08/01/2021: Answer is 6.
w = total weight of boxes is given as 480.
t = number of 30 pound boxes is given as 12.
Plug the above values in the equation to determine the number of 20 pound boxes = n.
w = 20n + 30t --> 480 = 20n + (30 x 12) --> 480 = 20n + 360 --> 20n = 120 --> n = 6