Renna pushed the button for the elevator to go up, but it would not move. the weight limit for the elevator is 450 kilograms, but the current group of passengers weighs a total of 750 kilograms. renna wants to determine how many 70-kilogram passengers need to get off the elevator.

Here is the solution based on the given situation above.
Given: 450 kg = weight limit of the elevator
           750 kg = current weight of the group of passengers
           ? = number of passengers who weigh 70 kgs that need to get off the elevator
So to get the answer, first we need to deduct 450kg from 750 kgs to get the excess weight. So 750 - 450 is 300kgs. Next, we divide 300 by 70kgs to get the number of passengers that need to get off so 300/70 is 4.3. Therefore, there should be 4 passengers who weigh 70 kilograms that need to get off the elevator.