Final answer:
The total number of sit-ups completed by Vitor and Manuela is 160, as both did 80 sit-ups individually.
Step-by-step explanation:
The total number of sit-ups completed by Vitor and Manuela is the sum of the sit-ups each of them completed. Since both Vitor and Manuela completed 80 sit-ups each, we add 80 (for Vitor) and 80 (for Manuela) together to get the total.
80 sit-ups (Vitor) + 80 sit-ups (Manuela) = 160 sit-ups
Therefore, the total number of sit-ups completed by Vitor and Manuela is 160.