Thank you for the opportunity to help you with your question! the solution is as such:
R1= log10 (x/ xo)
so, R1= log10 (6.6/ 4.8)
R2= log10 (7.1/ 4.8)
R2/ R1 = 0.17 / 0.138
R2/ R1= 1.23 TIMES
THEREFORE THE SECOND EARTHQUAKE WAS 1.23 TIMES STRONGER THAN FIRST ONE.
Please let me know if you need any clarification. I'm always happy to answer your questions.awaiting a positive feedback. It was lovely helping you. in case of a wrong answer or doubt please discuss before taking any action. Please do contact or tex