Amit can do 50% more work than Bhushan in same time. Bhushan alone can do a piece of work in 30 hours. Bhushan starts working and had already worked for 12 hours when Amit joins him. How many hours should Bhushan and Amit work together to complete the remaining work?

A

6 hours

B

12 hours

C

4.8 hours

D

7.2 hours