In alternative learning environment, students attempted the practice quiz multiple times to familiarize the online$-$test environment.

Dr$.$ Vettri wants to establish the actual exam time based on the completion time of the practice quiz. However, a technical glitch with the CANVAS system provided only the completion times for Attempt $2$ and Attempt $4$ which were $42$ minutes and $30$ minutes respectively.

Dr$.$ Vettri has decided to use the completion time for Attempt $3$ as a basis for establishing the actual exam time. Determine the completion time for Attempt $3$ using the concept of learning curve. $($Round$-$up to the nearest minute$)$