Answer:
45 secs
Step-by-step explanation:
Mike spent 30s on each of the first 60 questions. In total, he spent 30mins on the first 60 questions (30s per q, 30*60=1800s. 1800s/60=30mins).
Therefore he has a further 30mins left to complete the last 40 questions:
1800s/40=45 seconds