3. "That" and "this", plus half of "that" and "this" - what percentage of three quarters of "that" and "this" would this be?
3. "That" and "this", plus half of "that" and "this" - this is one and a half "that" and "this", which is twice as much as three quarters of "that" and "this", i.e., it constitutes $200 \%$ of them.

Answer: $200 \%$.