If one sound is 10^x times more intense than another sound, then it has a sound level which is 10*x more decibels than the less intense sound. So, 10*6=60=7.75^2≈60
The difference starts off by 7. Then it continues to double. Then the answer is 14, 28, 42. The answer doubles every time.
$9000000 you do this by doing 4,500,000*2 you can do this working it out or calculator