11 * 11 = 121. The star means multiply btw.
If Gina has $90 and pays:
$20 for beginning
$5 per hour
Then 90 - 20 is 70. 70 divided by 5 is 14.
She can rent a surfboard to surf for 14 hours.
1. The combined volume of all the tanks at the aquarium is written in Scientific notation. Keeping this on mind, you can write it as following:

2. Now, you must sum the combined volume of all the tanks and the volume of the new tank to calculate the total volume of all of them:
3. Now, you can write the result in Scientific notation, as following:

The answer is: 
The answer would be 11.
I hope that this will help somebody :)
D you only need that much